GRB 201015A
GCN Circular 28632
Subject
GRB 201015A: Swift detection of a burst
Date
2020-10-15T22:58:36Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
V. D'Elia (SSDC), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), J.D. Gropp (PSU), N. J. Klingler (PSU),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), B. Sbarufatti (PSU) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 22:50:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 201015A (trigger=1000452). Swift did not slew immediately
to the burst due to an observing constraint.
The BAT on-board calculated location is
RA, Dec 354.343, +53.393 which is
RA(J2000) = 23h 37m 22s
Dec(J2000) = +53d 23' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 10 sec. The peak count rate
was ~700 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+51.6
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is V. D'Elia (delia AT ssdc.asi.it).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular 28634
Subject
Swift GRB 201015A: Global MASTER-Net observations report
Date
2020-10-15T23:02:53Z (5 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin,
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov, D. Cheryasov
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 201015A ( V. D'Elia et al., GCN 28632) errorbox 88 sec after trigger time at 2020-10-15 22:51:41 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 33 deg. The sun altitude is -50.5 deg.
The galactic latitude b = -8 deg., longitude l = 112 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1462183
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
98 | MASTER-Tavrida | C | 20 | 17.8 |
123 | MASTER-Tavrida | C | 70 | 18.5 | Coadd
138 | MASTER-Tavrida | C | 20 | 17.9 |
184 | MASTER-Tavrida | C | 30 | 18.1 |
239 | MASTER-Tavrida | C | 40 | 18.3 |
305 | MASTER-Tavrida | C | 50 | 18.4 |
385 | MASTER-Tavrida | C | 70 | 18.5 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 28635
Subject
GRB 201015A: Swift-XRT observations
Date
2020-10-16T00:11:29Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), G. Tagliaferri (INAF-OAB), S. Campana (INAF-OAB),
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows
(PSU) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 201015A at 23:43:47.2 UT,
3214.1 seconds after the BAT trigger. Using promptly downlinked data we
find a fading, uncatalogued X-ray source located at RA, Dec 354.32067,
53.41460 which is equivalent to:
RA(J2000) = 23h 37m 16.96s
Dec(J2000) = +53d 24' 52.6"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 91 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 3.60
x 10^21 cm^-2 (Willingale et al. 2013).
GCN Circular 28637
Subject
GRB 201015A: NOT optical afterglow confirmation
Date
2020-10-16T01:21:02Z (5 years ago)
From
Daniele B Malesani at DTU Space <malesani@space.dtu.dk>
D. B. Malesani (DTU Space), A. de Ugarte Postigo (HETH, IAA/CSIC), T.
Pursimo (NOT), report on behalf of a larger collaboration:
We observed the field of GRB 201015A (D'Elia et al., GCN 28632) using
the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Our
first image was taken at 23:25:12 UT (35 min after the trigger). At the
location of the afterglow candidate reported by Lipunov et al. (GCN
28633), also consistent with the XRT position (Kennea et al., GCN
28635), we detect a source not visible in the Pan-STARRS images of the
same area. We report for this target the following, refined coordinates:
RA(J2000) = 23:37:16.41
Dec(J2000) = +53:24:56.5
with an uncertainty of 0.3" (calibrated against the Gaia catalog).
Our image was taken with a non-standard, broad filter (~3700-9000 AA),
and the target is affected by a saturation defect from a star. We cannot
provide a reliable magnitude at the present time, but a rough estimate
yields ~19.
GCN Circular 28639
Subject
GRB 201015A: GOTO confirmation of afterglow detection
Date
2020-10-16T03:18:47Z (5 years ago)
From
Kendall Ackley at Monash University <kendall.ackley@monash.edu>
K. Ackley (1); D. K. Galloway (1); Y-L Mong (1); M. Dyer (2); J. Lyman (3);
K.
Ulaczyk (3); D. Steeghs (3); V. Dhillon (2); P. O'Brien (4); G. Ramsay
(5); S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); D. Pollacco
(3); R. Breton (9)
((1) Monash University, (2) University of Sheffield, (3) Warwick
University, (4) University of Leicester, (5) Armagh Observatory &
Planetarium, (6) National Astronomical Research Institute of Thailand,
(7) University of Turku, (8) University of Portsmouth, (9) University
of Manchester)
report on behalf of the GOTO collaboration:
We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO) on La Palma in response to GRB 201015A
(Swift; D'Elia et al; GCN 28632).
We made a series of 4x90 s exposures using our wide L-band filter
(400-700 nm) covering the Swift XRT error box (Swift; Kennea et al.; GCN
28635),
beginning at 51 minutes after trigger, with midtime of the
first observation 23:41:54.25 UT on 15 October 2020.
Using a difference imaging analysis with recent survey observations of
the same pointings as reference, we detect an uncatalogued source
located at (J2000):
RA 23:37:16.42
Dec +53:24:55.89
confirming the OT reported by MASTER (Lupinov et al.; GCN 28633) and
NOT (Malesani et al.; GCN 28637). We find an equivalent magnitude of
g ~ 20.2 mag based on cross-calibration of our L-band magnitudes
against the ATLAS catalogue.
Observations are continuing.
GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC) (https://goto-observatory.org
<https://goto-observatory.org/>)
GCN Circular 28645
Subject
GRB 201015A: BOOTES-1 early optical afterglow detection
Date
2020-10-16T05:18:34Z (5 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco, I. Perez-Garcia, A. Reina (Univ. de Malaga) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:
Following the Swift/BAT trigger of GRB 201015A (D'Elia et al., GCNC 28632), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst. A series of images were taken starting on 15 Oct at 22:50:48UT (35 s after trigger). We confirm the OT reported by MASTER (Lipunov et al., GCNC 28633) in our co-added 30x1s clear filter images at a similar epoch (T_mid = 205 s) with 17.0 mag, at a position consistent with the reported Swift/XRT X-ray (Kennea et al., GCNC 28635) and late-time optical afterglows position reported by NOT (Malesani et al., GCNC 28637) and GOTO (Ackley et al., GCNC 28639). Further analysis is ongoing.
We thank the staff at INTA-CEDEA for their excellent support.
GCN Circular 28647
Subject
GRB 201015A: Enhanced Swift-XRT position
Date
2020-10-16T06:48:24Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1576 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 201015A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 354.31859, +53.41603 which is equivalent
to:
RA (J2000): 23h 37m 16.46s
Dec (J2000): +53d 24' 57.7"
with an uncertainty of 1.7 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 28649
Subject
GRB 201015A: Redshift from GTC/OSIRIS
Date
2020-10-16T09:13:32Z (5 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D.A. Kann, M. Blazek, J.F. Agui Fernandez, C. Thoene (all HETH/IAA-CSIC), G. Gomez Velarde (GTC) report:
We observed the afterglow of GRB 201015A (D���Elia et al. GCN 28632, Lipunov et al. GCN 28633) with the 10.4m GTC telescope, at Roque de los Muchachos Observatory (La Palma, Spain) equipped with OSIRIS. The observation started at 4:07 UT (5.28 hrs after the GRB onset) and consisted of 3x900s with the R1000B grism, covering the range between 3700 and 7800 ��.
The spectrum shows a featureless continuum throughout the full spectral range. However, we do identify emission features superposed on the trace, which we identify as [OIII], [OII], and H-beta at a common redshift of 0.426.
The automatic BAT analysis shows that this is a peculiar short but soft spectrum burst. We encourage follow-up to search for the associated supernova that could confirm the long nature of the burst, or the lack of such a supernova which would indicate a possible short origin.
GCN Circular 28653
Subject
GRB201015A: Nanshan/NEXT early optical observations
Date
2020-10-16T14:16:04Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC/HUST), X. Liu, S.Y. Fu, D. Xu (NAOC), X. Gao (Urumqi No.1
Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 201015A (D'Elia et al., GCN 28632) using
the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China.
Observations automatically started at 22:51:31 UT on 2020-10-15, i.e.,
78 s after the BAT trigger. We obtained 3x40s, 4x60s and 12x90s frames
in the Sloan r-filter until the sky brightens.
The optical afterglow (e.g., Lipunov et al., GCN 28633; Kennea et al.,
GCN 28635; Malesani et al., GCN 28637; Ackley et al., GCN 28639; Hu et
al., GCN 28645) is clearly detected in our images. The lightcurve rises
from r = 18.34 +/- 0.08 at T-mid=98 s to the peak of r = 16.97 +/- 0.03
at T-mid=226 s, and then decays roughly in a powerlaw with the index of
alpha ~ 1.2. Photometry is calculated with the Pan-STARRS field.
GCN Circular 28656
Subject
GRB 201015A: CrAO/ZTSH optical observations
Date
2020-10-16T15:31:16Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), N. Pankov (HSE), A. Pozanenko (IKI), V. Rumyantsev
(CrAO), A. Volnova (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the GRB 201015A (D'Elia et al., GCN 28632) with ZTSH 2.6m
telescope of CrAO observatory between Oct. 16 (UT) 01:02:14 -- 02:52:23.
The optical afterglow (e.g., Lipunov et al., GCN 28633; Kennea et
al., GCN 28635; Malesani et al., GCN 28637; Ackley et al., GCN 28639; Hu
et al., GCN 28645; Zhu et al., GCN 28653) at redshift z=0.426 (de Ugarte
Postigo et al., GCN 28649) is clearly detected in each frame of 120 s
exposure in R filter.
The exact photometry of the afterglow depends on the underlying object
visible and presented in PS1 catalogue (i'=19.6), which may be a host
galaxy (PS1 magnitude i'=19.6). Preliminary photometry of the afterglow
in a combined image is following
Date UT start t-T0 Filter Exp. OT err UL(3sigma)
(mid, days) (s)
2018-10-16 02:19:26 0.15501 R 12*120 20.66 0.05 23.0
The photometry is based on several nearby USNO-B1.0 stars
USNO-B1.0_id R2
1434-0471702 17.51
1434-0471746 18.23
GCN Circular 28658
Subject
GRB 201015A: Swift-BAT refined analysis (a soft short pulse with a tail emission)
Date
2020-10-16T16:04:58Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), V. D'Elia (SSDC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 201015A (trigger #1000452)
(D'Elia et al., GCN Circ. 28632). The BAT ground-calculated position is
RA, Dec = 354.310, 53.446 deg which is
RA(J2000) = 23h 37m 14.4s
Dec(J2000) = +53d 26' 45.0"
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.
The mask-weighted light curve shows a short-soft structure with several
overlapping pulses that start at ~T0 and end at ~T+1 s, followed by
a weak-soft tail that lasts till ~T+10 s. T90 (15-350 keV)
is 9.78 +- 3.47 sec (estimated error including systematics).
The time-averaged spectrum from T+0.02 to T+10.35 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 3.03 +- 0.68. The fluence in the 15-150 keV band
is 2.0 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured
from T+0.08 sec in the 15-150 keV band is 1.8 +- 0.4 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.
The BAT spectrum of this event does not appear to be a short hard burst.
However, the quickly fading X-ray and optical afterglows are
consistent with those from a short GRB.
If this is a short GRB, this is one of the softest short bursts
detected by BAT (based on a sample with constrained spectral fits
from the 3rd BAT GRB catalog; Lien & Sakamoto et al. 2016).
Other BAT-detected short GRBs with similar softness include
GRB190326A and GRB140622A. GRB190326A has an ambiguous
origin due to an observing constraint, but late time XRT/UVOT
followup observations suggest that the source is more consistent
with a GRB (Sbarufatti et al., GCN Circ. 24129). GRB140622A was
classified to be a short GRB because the XRT light curve is
consistent with the normal behavior of a short burst
(Sakamoto et al. GCN Circ. 16438; Burrows et al. GCN Circ. 16439).
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1000452/BA/
GCN Circular 28659
Subject
MAGIC observations of GRB 201015A: hint of very high energy gamma-ray signal
Date
2020-10-16T16:48:37Z (5 years ago)
From
Oscar Blanch at MAGIC Collaboration <blanch@ifae.es>
O.Blanch (IFAE-BIST Barcelona), M. Gaug (UAB Barcelona), K. Noda (ICRR University of Tokyo),
A. Berti (INFN Torino), E. Moretti (IFAE-BIST Barcelona), D. Miceli (University of Udine and INFN Trieste),
P. Gliwny (University of Lodz) S. Ubach (UAB Barcelona), B. Schleicher (University of Wuerzburg),
M. Cerruti (University of Barcelona) and A. Stamerra (INAF Rome) on behalf of the MAGIC collaboration
report:
On October 15, 2020, the MAGIC telescopes observed GRB 201015A following the Swift-BAT trigger (D���Elia et al., GCN 28632).
MAGIC started observations under good conditions about 40 seconds after the initial Swift trigger, revealing a hint of signal
with significance >3 sigma in the very high energy band. Refined off-line analyses of the data are ongoing.
Further MAGIC observations on GRB 201015A are planned in the coming night. We strongly encourage follow-up
observations by other instruments at all wavelengths.
The MAGIC point of contact for this burst is O. Blanch (blanch@ifae.es). Burst Advocate for this burst is
M. Gaug (Markus.Gaug@uab.cat)
MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes
located at the Observatory Roque de los Muchachos on the Canary island
La Palma, Spain, and designed to perform gamma-ray astronomy in the energy
range from 50 GeV to greater than 50 TeV.
--
Av��s -
Aviso - Legal Notice - (LOPD) - http://legal.ifae.es
<http://legal.ifae.es/>
GCN Circular 28660
Subject
GRB 201015A: Swift-XRT refined Analysis
Date
2020-10-16T17:26:09Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. D'Ai (INAF-IASFPA), J. D. Gropp (PSU), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), A. Melandri (INAF-OAB) and V.
D'Elia report on behalf of the Swift-XRT team:
We have analysed 7.2 ks of XRT data for GRB 201015A (D'Elia et al. GCN
Circ. 28632), from 3.2 ks to 57.3 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 28647).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.49 (+0.24, -0.21).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.2 (+/-0.4). The
best-fitting absorption column is 2.3 (+4.6, -2.3) x 10^21 cm^-2, at a
redshift of 0.426, in addition to the Galactic value of 3.6 x 10^21
cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x
10^-11 (7.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 3.6 x 10^21 cm^-2
Intrinsic column: 2.3 (+4.6, -2.3) x 10^21 cm^-2 at z=0.426
Photon index: 2.2 (+/-0.4)
If the light curve continues to decay with a power-law decay index of
1.49, the count rate at T+24 hours will be 10.0 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.0 x
10^-14 (7.7 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01000452.
This circular is an official product of the Swift-XRT team.
GCN Circular 28661
Subject
GRB 201015A: redshift confirmation
Date
2020-10-16T18:15:26Z (5 years ago)
From
Daniele B Malesani at DTU Space <malesani@space.dtu.dk>
L. Izzo (DARK/NBI), D. B. Malesani (DTU Space), Z.P. Zhu (NAO/CAS,
HUST), D. Xu (NAO/CAS), A. de Ugarte Postigo (HETH, IAA-CSIC), T.
Pursimo, report on behalf of a larger collaboration:
We observed the optical counterpart of GRB 201015A (D'Elia et al., GCN
28632; Lipunov et al., GCN 28634) with the Nordic Optical Telescope,
equipped with the ALFOSC spectrograph. Spectroscopic observations
started on 2020 Oct 15.978 UT (38 min after the GRB trigger) and
consisted of four 900-s exposures with grism #4, covering the wavelength
range 3800-9400 AA.
A trace is visible across the full spectral range. In the blue part,
weak absorption features are detected which can be interpreted as Mg II,
Mg I and Ca II at z = 0.423. Faint emission lines are also detected at a
consistent redshift, identified as [O II] and Halpha. Our data allow
thus to confirm the redshift value reported by de Ugarte Postigo et al.
(GCN 28649) using the GTC. We note that the detection of absorption
features sets a firm lower limit to the GRB redshift, excluding a chance
superposition with a background galaxy.
This work made use of the GRBspec database grbspec.iaa.es.
GCN Circular 28662
Subject
GRB 201015A: Swift/UVOT Detection
Date
2020-10-16T20:49:02Z (5 years ago)
From
Frank Marshall at Swift/UVOT <marshall@milkyway.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and V. D'Elia (SSDC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201015A
3217 s after the BAT trigger (D'Elia et al., GCN Circ. 28632).
A weak source consistent with the optical position
(Malesani et al. GCN Circ. 28637)
is detected in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 3217 3367 147 20.69 +/- 0.28
white 4402 4602 197 20.33 +/- 0.16
v 3375 4949 331 >19.3
b 4197 4397 197 20.47 +/- 0.33
u 3991 4191 197 >19.7
w1 3786 3986 197 >19.3
m2 3579 3779 197 >18.8
w2 4608 4808 197 >19.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.34 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 28663
Subject
Fermi GBM Sub-Threshold Detection of GRB 201015A
Date
2020-10-16T21:25:33Z (5 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
C. Fletcher (USRA) and P. Veres (UAH) report on behalf of the Fermi-GBM Team:
Swift-BAT detected GRB 201015A at 22:50:13 UT (GCN 28632). There was no
Fermi-GBM onboard trigger around the event.
An automated, blind search for short gamma-ray bursts below the onboard
triggering threshold in Fermi-GBM identified no counterparts.
The GBM targeted search [1], the most sensitive, coherent search for
GRB-like signals was run from +/-30 s around the BAT trigger time. A transient source was
identified whose most significant timescale according to the automated search is 1.024 s,
with a log likelihood ratio of 76 and a location consistent with the Swift-BAT event.
The time-averaged spectrum from T0-0.256 s to T0+0.896 s is adequately fit by a
Band function with Epeak = 14 +/- 6 keV, alpha = -1.0 (fixed), and beta = -2.40
+/- 0.21. Because the peak energy is close to the low energy threshold of GBM,
the low energy photon index is unconstrained. We fix it to the median value of
the GBM GRB sample, however it has no significant effect on the values for Epeak and beta.
The event fluence (10-1000 keV) in this time interval is(2.25 +/- 0.38)E-07 erg/cm^2.
T0 here is 2020-10-15T22:50:13.22 UT = 624495018.22 (MET)
[1] Goldstein et al. 2019 arXiv:1903.12597
GCN Circular 28664
Subject
GRB 201015A: FRAM-ORM afterglow detection
Date
2020-10-17T06:24:03Z (5 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ),
Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek,
Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza
(Institute of Physics, Prague, CZ)
report:
The 25cm robotic telescope FRAM-ORM at La Palma (Spain)
reacted robotically to the alert of GRB201015A (D'Elia
et al GCNC 28632), obtaining a series of 20 s unfiltered
images starting at 22:50:50.8 UT, i.e. 37.6s post trigger.
We clearly detect the source reported by other telescopes
(Lipunov et al. GCN 28633, Malesani et al GCN 28637, Ackley
et al GCN 28639 and others). As reported before, the
brightness of the object reaches a maximum about 5 minutes
after the trigger with R ~ 16.5 and then decays until the
end of our dataset 2.4 h after the trigger.
GCN Circular 28668
Subject
GRB 201015A: classification as long GRB
Date
2020-10-17T12:55:23Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
P. Minaev (IKI) and A. Pozanenko (IKI) report on behalf of larger GRB
follow-up collaboration:
We analyzed GRB 201015A detected by Swift (D'Elia et al., GCN 28632)
using GBM/Fermi spectral data (Fletcher et al., GCN 28663) and redshift
of z = 0.426 (de Ugarte Postigo et al., GCN 28649; Izzo et al., GCN
28661). GRB 201015A has a low luminosity, Eiso = (1.1 +/- 0.2)*10^50
erg, and well consistent with the Ep,i ��� Eiso correlation (Amati
relation) for type II (long) bursts, see [1] for details and Figure at
http://grb.rssi.ru/GRB201015A/GRB201015A_Epi_Eiso.png
The position of the burst is within 1-sigma confidence area of the
cluster of type II (long) bursts on the EH ��� T90,i diagram (see [2] for
details), indicating strong association with type II bursts, see Figure at
http://grb.rssi.ru/GRB201015A/GRB201015A_EH_T90i.png
We encourage follow-up optical observations to search for associated
supernova.
[1] - Minaev et al., MNRAS, 492, 1919, 2020
[2] - Minaev et al., arXiv:2008.12752
GCN Circular 28673
Subject
GRB 201015A: Assy and Mondy optical observations
Date
2020-10-17T15:56:12Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), V. Kim (AFIF, Pulkovo Observatory), A. Pozanenko (IKI),
E. Klunko (ISTP), M. Krugov (AFIF), N. Pankov (HSE), A. Volnova (IKI)
report on behalf of IKI GRB FuN:
We observed GRB 201015A (D'Elia et al., GCN 28632) with AZT-33IK
telescope of Mondy observatory in R-filter starting on Oct. 16 (UT)
13:42:54 and with AZT-20 telescope of Assy-Turgen observatory starting
on Oct. 16 (UT) 14:51:35 in g',r',i'-filters. The optical afterglow
(e.g., Lipunov et al., GCN 28633; Kennea et al., GCN 28635; Malesani et
al., GCN 28637; Ackley et al., GCN 28639; Hu et al., GCN 28645; Zhu et
al., GCN 28653) at redshift z=0.426 (de Ugarte Postigo et al., GCN
28649; Izzo et al., GCN 28661) is detected in stacked images in each filter.
Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err. UL (3sigma)
(mid, days) (s)
2020-10-16 13:42:54 0.64075 R 30*120 21.70 0.25 22.0
2020-10-16 14:51:35 0.68081 r'(AB) 36*60 21.85 0.14 23.5
2020-10-16 15:02:53 0.68796 g'(AB) 36*60 22.10 0.10 23.7
The photometry is based on the nearby stars of PanSTARRS-PS1 catalog.
RA, DEC, g, r, i
23:37:17.49934 +53:24:05.6357 18.6327 17.7832 17.4125
23:37:21.06032 +53:24:57.1308 19.4472 18.4947 18.0340
GCN Circular 28674
Subject
GRB 201015A NUTTelA-TAO / BSTI Early Measurements (Preliminary)
Date
2020-10-18T00:01:47Z (5 years ago)
From
Bruce Grossan at LBNL/UCB SSL <Bruce_Grossan@lbl.gov>
B. Grossan (UCB, NU) , Z. Maksut (NU), A. Kim (NU), M. Krugov (FAI), G. F. Smoot (HKUST, UCB, NU), E. Linder (UCB, NU), report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB201015A on receipt of an automated GCN / BAT position alert. We report measurements made with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32,14) instrument ***during commissioning phase*** and we note cautions with these measurements below.
Calibration with bright Pan-STARRS catalog I stars on our images, for our standard SDSS filters yields, without color corrections, the following photometric values for the OT:
tc-t0(s) g'(mag) r'(mag) i'(mag)
-------- ------- -------- ------------
73.2 UL17.8 17.79 17.67
103.2 UL17.8 18.16 17.86
157.6 17.91 16.81 16.96
202.6 17.76 16.63 16.75
247.6 17.94 16.86 16.85
292.6 17.89 17.29 16.87
337.6 17.76 17.02 17.01
382.6 18.21 17.31 17.05
427.6 18.07 17.49 17.16
472.6 18.08 17.56 17.29
517.6 18.31 17.60 17.48
562.6 18.14 17.90 17.66
607.6 18.61 18.00 17.49
652.6 UL18.2 18.13 17.85
697.6 UL18.2 18.37 18.00
742.6 UL18.2 18.53 18.02
787.6 UL18.2 18.45 18.06
832.6 UL18.2 18.41 18.34
877.6 UL18.2 18.71 UL17.9
922.6 UL18.2 18.85 18.21
967.6 UL18.2 UL18.2 18.26
1012.6 UL18.2 UL18.2 UL17.8
1057.6 UL18.2 UL18.2 UL17.8
1102.6 UL18.2 UL18.2 UL17.8
1147.6 UL18.2 UL18.2 UL17.8
1192.6 UL18.2 UL18.3 UL17.8
UL = 5 sigma upper limit
Uncertainties are estimated at ~ 0.1 mag for r',i'; unfortunately at this time we have indications of errors ~ 0.15 mag for g'.
tc-t0 = trigger time minus image center time. We have not yet established the accurracy of our times.
The first two co-adds are 30 s in duration; the rest are 45 s.
The peak in r' at ~200 s is roughly consistent with that of other observers (e.g. see Dong Xu, 2020, GCN 28653), but for precise comparisons see cautionary notes below.
These measurements are likely among the earliest multi-channel simultaneous optical measurements of GRBs. We encourage additional measurements at all wavelengths to add to these data.
We caution the reader that the BSTI instrument is in commissioning phase, with known imperfections, and we have not extensively tested our results, e.g. against other simultaneous measurements, or near our detection limits. Please also note that the times are approximate. We anticipate additional refinement and improvement in analysis in 15-30 days posted at http://ecl.nu.edu.kz/gamma-ray-burst/grb201015A.
----------------------------------
UCB = University of California, Berkeley, USA
NU = Nazarbayev University, Nur-Sultan, Kazakhstan
HKUST = Hong Kong University of Science and Technology
FAI = Fesenkov Astrophysical Institute, Kazakhstan
The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan.
GCN Circular 28676
Subject
GRB 201015A: MMT afterglow imaging
Date
2020-10-18T03:28:43Z (5 years ago)
From
Jillian Rastinejad at Northwestern Univ. <jillianrastinejad2024@u.northwestern.edu>
J. Rastinejad, K. Paterson, C. D. Kilpatrick and W. Fong (Northwestern) report:
''We observed the location of Swift GRB 201015A (D'Elia et al., GCN 28632; Markwardt et al., GCN 28658) with the Binospec imager and spectrograph mounted on the MMT 6.5-meter telescope on Mount Hopkins, Arizona. We obtain 6x120-sec imaging in the i-band and 9x120-sec imaging in the z-band at mid-times of 2020 October 17.365 (1.41 days post-burst) and 2020 October 17.342 (1.39 days post-burst), respectively. Within the XRT position (Evans et al. GCN 28647), we detect the previously reported optical afterglow (Lipunov et al. GCN 28633; Malesani et al; GCN 28637, Hu et al.; GCN 28645, Zhu et al.; GCN 28653; Belkin et al. GCN 28656; Jelinek et al., GCN 28664; Belkin et al., GCN 28673). Calibrated to PS1, we measure i = 22.2 +/- 0.1 mag and z = 21.9 +/- 0.1 mag (AB system and not corrected for Galactic extinction in the direction of the burst).
In addition to the afterglow, emission extending directly to the southwest of the afterglow position is weakly detected in both bands, at around RA(J2000) = 23:37:16.35, Dec(J2000)=+53:24:55.7. Given its proximity to the afterglow, this may be the host galaxy of GRB 201015A; however our imaging cannot resolve the afterglow from this extended emission. We also detect the brighter galaxy, previously mentioned in Belkin et al. (GCN 28656) and also detected in archival PS1 imaging at an offset of 2.3'' from the afterglow position (Malesani et al., GCN 28637). Given the large offset from the afterglow (13 kpc at z=0.42; de Ugarte Postigo et al., GCN 28649, Izzo et al., GCN 28661), we consider that this source is less likely to be related to the GRB.
Further observations are planned. We thank Skyler Self and Ben Weiner at the MMT for the rapid scheduling and execution of these observations.''
GCN Circular 28677
Subject
GRB 201015A: Xinglong-2.16m optical observations
Date
2020-10-18T06:29:12Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), X. Liu, S.Y. Fu, D. Xu (NAOC) report:
We observed the field of GRB 201015A (D'Elia et al., GCN 28632; Kennea
et al., GCN 28635) using the Xinglong-2.16m telescope equipped with the
BFOSC. Observations were carried out starting at 10:35:46 UT on
2020-10-16 (i.e., about 11.2 hr after the BAT trigger), and 13x300s
R-band frames were obtained.
The GRB optical afterglow (e.g., Lipunov et al., GCN 28633; Malesani et
al., GCN 28637; Ackley et al., GCN 28639; Hu et al., GCN 28645; Zhu et
al., GCN 28653; Belkin et al., GCN 28673; Jelinek et al., GCN 28664;
Marshall et al., GCN 28662; Belkin et al., GCN 28656; Grossan et al.,
GCN 28674) is weakly detected in our stacked image, with R = 22.0 +/-
0.3 at T-mid=12.10 hr, calibrated with the nearby Pan-STARRS field.
We acknowledge the support of the staff of the Xinglong-2.16m telescope,
in particular J. Zheng and A.Y. Zhou.
GCN Circular 28680
Subject
GRB 201015A: HCT optical photometric follow-up
Date
2020-10-18T15:11:04Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), D. K. Sahu (IIA), R. Gupta (ARIES), V. Shenoy (IITB), B.
Kumar (ARIES), S. Kiran (IIA), G. C. Anupama (IIA), V. Bhalerao (IITB),
S.B. Pandey (ARIES), S. Barway (IIA), report on behalf of the HCT team:
We observed GRB 201015A reported by Swift-BAT (V. D'Elia et al., GCN
28632; also see: V. Lipunov et al., GCN 28633; J.A. Kennea et al., GCN
28635; D. B. Malesani et al., GCN 28637; K. Ackley et al., GCN 28639; Y.-D.
Hu et al., GCN 28645; P.A. Evans et al., GCN 28647; A. de Ugarte Postigo et
al., GCN 28649; Z.P. Zhu et al., GCN 28653; S. Belkin et al., GCN 28656; C.
B. Markwardt et al., GCN 28658; A. D'Ai et al., GCN 28660; L. Izzo et al.,
GCN 28661; F. E. Marshall et al., GCN 28662; C. Fletcher et al., GCN
28663; Martin Jelinek and Jan Strobl et al., GCN 28664; P. Minaev et al.,
GCN 28668; S. Belkin et al., GCN 28673; B. Grossan et al., GCN 28674; J.
Rastinejad et al., GCN 28676; Z.P. Zhu et al., GCN 28677) with 2.0 m
Himalayan Chandra Telescope (HCT). The field was observed in the V and Rc
filter starting at 2020-10-16T17:54:14.936 UT i.e. ~19 hrs after the event
detection by Swift-BAT. We obtained 9 x 60 sec in Rc and 120 x 9 in the V
band. We clearly detected the source in the stacked image.
We obtained the following photometric results:-
------------------------------------------------------------------
JD(Mean) | Filter | Mag | Total exposure (sec) |
------------------------------------------------------------------
2459139.250567 | V | 21.56 +/- 0.1 | 60 x 9
2459139.262356 | Rc | 21.33 +/- 0.04 | 120 x 9
------------------------------------------------------------------
These observations were carried out under the ToO program HCT-2020-C3-P6.
We thank HCT staff for conducting the observations.
GCN Circular 28681
Subject
GRB 201015A: GROWTH-India Telescope (GIT) upper limit
Date
2020-10-18T19:03:03Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), U. Stanzin(IAO), V. Bhalerao (IITB), G. C. Anupama (IIA),
S. Barway (IIA) report on behalf of the GROWTH-India collaboration:
We observed GRB 201015A reported by Swift-BAT (V. D'Elia et al., GCN
28632; also see: V. Lipunov et al., GCN 28633; J.A. Kennea et al., GCN
28635; D. B. Malesani et al., GCN 28637; K. Ackley et al., GCN 28639; Y.-D.
Hu et al., GCN 28645; P.A. Evans et al., GCN 28647; A. de Ugarte Postigo et
al., GCN 28649; Z.P. Zhu et al., GCN 28653; S. Belkin et al., GCN 28656; C.
B. Markwardt et al., GCN 28658; A. D'Ai et al., GCN 28660; L. Izzo et al.,
GCN 28661; F. E. Marshall et al., GCN 28662; C. Fletcher et al., GCN
28663; Martin Jelinek and Jan Strobl et al., GCN 28664; P. Minaev et al.,
GCN 28668; S. Belkin et al., GCN 28673; B. Grossan et al., GCN 28674; J.
Rastinejad et al., GCN 28676; Z.P. Zhu et al., GCN 28677, H. Kumar et al.,
GCN 28680) with 0.7m GROWTH-India Telescope (GIT). The field was observed
in the SDSS r��� filter starting at 2020-10-16T20:21:44.41 UT i.e. ~ 21.5 hrs
after the event detection by Swift-BAT. We obtained 10 exposures of 300 sec
each.
We did not find any source in the stacked image up to r��� > 20.97 mag (5-sigma)
within the uncertainty region, calibrated against PanSTARRs PS1 data
release (Flewelling et al., 2018).
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).
GCN Circular 28688
Subject
GRB 201015A: 6 GHz VLA radio afterglow candidate detection
Date
2020-10-19T14:53:30Z (5 years ago)
From
Wen-fai Fong at Northwestern U <wfong@northwestern.edu>
W. Fong, G. Schroeder, J. Rastinejad, and A. Hajela (Northwestern) report:
"We observed the position of GRB 201015A (D'Elia et al., GCN 28632; Markwardt et al., GCN 28658) with the Karl G. Jansky Very Large Array (VLA) beginning on 2020 Oct 17.364 UT (1.41 days post-burst) at a mean frequency of 6 GHz.
We detect a bright, uncatalogued radio source with a flux density of ~0.13 milliJy at the position:
RA(J2000) = 23:37:16.41
Dec(J2000) = +53:24:56.4
with an uncertainty of ~0.3" in each coordinate. This position is consistent with optical afterglow position reported by NOT (Malesani et al., GCN 28637), and the XRT position (Evans et al. GCN 28647). We propose this source as the radio afterglow of GRB 201015A.
We thank the VLA staff for quickly approving and executing these observations."
GCN Circular 28721
Subject
GRB 201015A: SAO RAS optical observations
Date
2020-10-21T13:48:37Z (5 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. S. Moskvitin, V. N. Aitov (SAO RAS)
on behalf of GRB follow-up team report.
We observed the field of the GRB 201015A (D'Elia et al., GCN #28632)
with the 1-m telescope of SAO RAS, Zeiss-1000 + Multi-Mode
Photometer-Polarimeter on October 16, 19:46:23--20:49:31 UT,
t_mid - T0 = 0.89426 days.
The GRB OT (Lipunov et al., GCN #28633; Malesani et al.,
GCN #28637; Ackley et al., GCN #28639; Hu et al., GCN #28645;
de Ugarte Postigo, GCN #28649; Zhu et al., GCN #28653; Belkin et al.,
GCN #28656; Izzo et al., GCN #28661; Marshall & D'Elia, GCN #28662;
Jelinek et al., GCN #28664; Belkin et al., GCN #28673;
Grossan et al., GCN #28674; Rastinejad et al., GCN #28676;
Zhu et al., GCN #28677; Kumar et al, #GCN 28680) is detected
in the stacked image. Preliminary photometry of the OT
is R = 21.69 +/- 0.05 (based on standards from Belkin et al.,
GCNs #28656, #28673).
GCN Circular 28822
Subject
GRB 201015A: Late X-ray Detections with Chandra
Date
2020-11-03T16:45:05Z (5 years ago)
From
Ben Gompertz at U of Warwick <b.gompertz@warwick.ac.uk>
B. Gompertz (1); A. Levan (2); N. Tanvir (3); A. Fruchter (4); A.
Cucchiara (5); J. Greiner (6); J. Hjorth (7); T. Kangas (4); G. Lamb
(3); J. Lyman (1); S. Oates (8); P. O'Brien (3); J. Osborne (3); K. Page
(3); D. Perley (9); E. Pian (10); D. Steeghs (1); K. Wiersema (1); G.
Wynn (3)
((1) University of Warwick, (2) Radboud University, (3) University of
Leicester, (4) Space Telescope Science Institute, (5) University of the
Virgin Islands, (6) MPE Garching, (7) University of Copenhagen, (8)
University of Birmingham, (9) Liverpool John Moores University, (10)
INAF-OAS)
report:
We observed the position of GRB 201015A (D'Elia et al., GCN 28632) with
the Chandra X-ray Observatory with epochs 8.4 and 13.6 days after
trigger. The X-ray afterglow is clearly detected with a flux around 100x
brighter than expected based on the extrapolation of the early XRT data
taken between 0.03 and 0.8 days after burst. The source is seen to fade
between the two Chandra epochs with a power-law index of approximately
-0.8. A Swift ToO has been approved.
GCN Circular 28857
Subject
GRB 201015A: Swift-XRT late time observations
Date
2020-11-06T17:24:55Z (5 years ago)
From
Valerio D'Elia at ASDC <valerio.delia@ssdc.asi.it>
V. D���Elia (SSDC) reports on behalf of the Swift team:
Following the Chandra late time detection (Gompertz et al., GCN Circ. 28822) of GRB 201015A (D���Elia et al., GCN Circ. 28632), Swift performed a ToO observation of its X-ray afterglow. 13 ks of data were acquired between 3 and 6 November, i.e., 18-21 days after the trigger. Consistent with the prediction reported by Gompertz et al., XRT detected the afterglow at a level of (7+/-3)E-4 cts/s.
This is an official product of the Swift-XRT team.
[GCN OPS NOTE(06nov2020): Per author's request, the tail end containing the signature block was removed.]
GCN Circular 28939
Subject
GRB 201015A radio afterglow with e-MERLIN
Date
2020-11-21T09:28:54Z (5 years ago)
From
Stefano Giarratana at University of Bologna <s.giarratana@ira.inaf.it>
S. Giarratana (Univ. of Bologna, INAF/IRA), M. Giroletti (INAF/IRA),
B. Marcote (JIV-ERIC), G. Ghirlanda (INAF/OABrera),
M. Rib�� (Univ. of Barcelona), J.M. Paredes (Univ. of Barcelona)
On UT 2020 November 5 and 8 we observed the radio counterpart of the
GRB 201015A (D���Elia V. et al., GCN Circ. 28632) with e-MERLIN at 5 GHz.
We detect a point-like source at a position consistent with the VLA
GRB 201015A afterglow coordinates (RA(J2000) = 23:37:16.41,
Dec(J2000)= +53:24:56.4, Fong W. et al., GCN Circ. 28688).
Preliminary analysis indicates a significance of the detection of 4.5
and 3.3 sigma confidence for November 5 and 8 observations respectively.
We note that the noise level in the November 8 observation is 20% higher
than on November 5.
Additional radio observations are in progress.
We would like to thank the e-MERLIN personnel for approving, executing,
and processing these observations.
GCN Circular 28945
Subject
GRB 201015A L-band observations with e-MERLIN
Date
2020-11-23T10:44:45Z (5 years ago)
From
Lauren Rhodes at Oxford <lauren.rhodes@physics.ox.ac.uk>
L. Rhodes, R. Fender (Oxford), J. Bray and D.R.A. Williams (JBCA) report:
e-MERLIN observed the position of GRB 201015A (D'Elia et al., GCN Circ. 28632) at 1.5GHz at 19 and 23 days post burst. Both epochs show a point source with coordinates consistent with those from the VLA detection (Fong et al., GCN Circ. 28688). The flux densities of the detections are 214+/-25uJy and 256+/-27uJy for epochs 1 and 2, respectively. We tentatively attribute the observed emission to the GRB�s host galaxy as there is very little variation in the flux density between our two epochs. There is also no significant variation between our detections and that from Fong et al., when using an optically thin spectrum to scale between the two observing bands.
We are in the process of obtaining further radio observations.
We thank the e-MERLIN staff for the time allocation and their assistance with the observations.
GCN Circular 29028
Subject
GRB 201015A: 5-GHz radio afterglow detection with the EVN
Date
2020-12-11T17:07:03Z (5 years ago)
From
Benito Marcote at JIVE <marcote@jive.eu>
B. Marcote (JIVE), M. Rib�� (Univ. of Barcelona), J. M. Paredes (Univ. of Barcelona), M. Giroletti (INAF/IRA), S. Giarratana (Univ. of Bologna, INAF/IRA), G. Ghirlanda (INAF/OABrera)
We observed the radio counterpart of GRB 201015A (D'Elia et al., GCN 28632) with the European VLBI Network (EVN) on 9 November 2020 and 1 December 2020 at a central frequency of 5.0 GHz.
Preliminary analysis reports the detection of a compact radio source at a >8-sigma confidence level in both epochs at a consistent position of:
RA (J2000) = 23h37m16.4223s
Dec (J2000) = +53d24'56.439"
With an uncertainty of ~1 mas on each coordinate. The synthesized beams are 1.1 x 2.1 mas (PA = 7.1 deg) and 3.1 x 3.6 mas (PA = -29 deg) for the first and second epoch, respectively. We note that this position is consistent with the one previously reported by the VLA (Fong et al. GCN 28688) and eMERLIN (Giarratana et al. GCN 28939).
Further analysis is in progress.
We thank the directors and staff of all the EVN telescopes for making this target of opportunity observation possible.
The European VLBI Network is a joint facility of independent European, African, Asian, and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from the following EVN project code: RM016. e-VLBI research infrastructure in Europe is supported by the European Union���s Seventh Framework Programme (FP7/2007-2013) under grant agreement number RI-261525 NEXPReS. e-MERLIN is a National Facility operated by the University of Manchester at Jodrell Bank Observatory on behalf of STFC.
GCN Circular 29033
Subject
GRB 201015A: optical observations and supernova identification
Date
2020-12-12T23:11:17Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), S. Belkin (IKI, HSE), A. Volnova (IKI), A. Moskvitin
(SAO RAS), O. Burhonov (UBAI), V. Kim (FAI), M. Krugov (FAI), V.
Rumyantsev (CrAO), E. Klunko (ISTP), R. Ya. Inasaridze (AbAO), I. Reva
(FAI), P. Minaev (IKI), N. Pankov (HSE), Sh. Ehgamberdiev (UBAI) report
on behalf of GRB IKI FuN:
We observed the GRB 201015A (D'Elia et al., GCN 28632) with ZTSh 2.6m
telescope of CrAO observatory, AZT-33IK of Mondy observatory, AZT-20 of
Assy observatory, AS-32 of Abastumani observatory, Zeiss-1000 of SAO
RAS, AZT-22 of Maidanak observatory, and Zeiss-1000(E) of TSHAO.
The optical transient of GRB 201015A (Lipunov et al., GCN 28633; Kennea
et al., GCN 28635; Malesani et al., GCN 28637; Ackley et al., GCN 28639;
Hu et al., GCN 28645; Zhu et al., GCN 28653; Belkin et al., 28656;
Marshall et al., GCN 28662; Jelinek et al., GCN 28664; Belkin et al.,
GCN 28673; Grossan et al., GCN 28674; Rastinejad et al., GCN 28676; Zhu
et al., GCN 28677; Kumar et al., GCN 28680; Kumar et al., GCN 28681;
Moskvitin et al., GCN 28721) at redshift z=0.426 (de Ugarte Postigo et
al., GCN 28649; Izzo et al., GCN 28661) is not spatially resolved in
most of our images besides a few imaging in Maidanak observatory between
Oct. 26 - Nov. 6 when observations were carried out under good weather
conditions (FWHM = 0.8 - 0.9 arcsec). The finding chart of stacked image
obtained in Maidanak observatory on Oct. 26, Nov. 4 and Nov. 6 is
presented in the left panel of the Figure 1.
http://grb.rssi.ru/GRB201015A/GRB201015A_SN_imaging.png
(In all of the stacked images in the Figure 1 we subtracted nearby stars
which positions are designated by white and green circles. The white
circles denote the stars presented in PS DR1 catalogue, and the green
circle denote the star is not presented in PS DR1. Stacked images of
Zeiss-1000 of SAO RAS observations on 32 days (central panel) and 47
days (right panel) are also presented in the Figure 1.)
Using the stacked image of Maidanak observations (left panel of the
Figure 1, an upper limit of the image is R=24.6) we obtained photometry
of the nearby stars. The photometry of the stars is used for flux
subtraction to obtain R-magnitudes of unresolved optical transient in
all of observations, and a light curve of the optical transient is
presented in Figure 2
http://grb.rssi.ru/GRB201015A/GRB201015A_SN_LC.png
The light curve is preliminary and represent the joint photometry of the
optical transient and a possible host galaxy.
The source raised on in the left panel of the Figure 1 (red circle)
coincides with an afterglow coordinates of GRB 201015A reported by NOT
observation (Malesani et al., GCN 28637). We suggest the object clearly
visible on Oct.26 - Nov.6 at the place of the afterglow is a supernova
associated with GRB 201015A. The light curve in the Figure 2 suggests
the supernova maximum between 12 and 20 days after GRB trigger. The
supernova identification rules out the GRB 201015A as a questionable
short burst with extended emission (Markwardt et al., GCN 28658) and
corroborates the GRB 201015A as a long duration burst (Minaev et al.,
GCN 28668). The afterglow in the first two days after the trigger can be
approximated by a power law with the index of -0.91 �� 0.03.
We apologize for late report due to delay of Maidanak data which is
critical for supernova identification.
GCN Circular 29306
Subject
GRB 201015A: evidence of supernova in LBT spectra
Date
2021-01-17T02:05:04Z (4 years ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
A. Rossi (INAF/OAS), S. Benetti (INAF-Padova), E. Palazzi (INAF/OAS), P.
D'Avanzo (INAF-OAB), V. D'Elia (SSDC), and M. De Pasquale report on
behalf of the CIBO collaboration:
We report the results of the photometric and spectroscopic follow-up of
GRB 201015A (D'Elia et al. GCN 28632) at z = 0.42 (Izzo et al. GCN
28661, de Ugarte Postigo et al. GCN 28649) obtained with the
Multi-Object Double Spectrographs (MODS) instrument mounted on the
2x8.4-m LBT telescope (Mt Graham, AZ, USA). Data were obtained at the
mid time of 04:00 UT on 2020-11-13, ~28.8 days after the burst trigger.
Spectroscopy of the source was obtained for a total of 8x900 s, covering
the wavelength range 3200-10000 AA. All the spectra have been corrected
for the Galactic extinction (A_V = 0.93). The low S/N spectrum shows a
peak around 5400 AA (rest frame) and is consistent with type Ic-BL
supernova spectra around maximum light, in agreement with the results
presented by Pozanenko et al. (GCN 29033).
Together with the spectroscopy we also obtained g and r-band imaging of
the supernova, which thanks to the good seeing of 0.6" it is separated
enough from the host galaxy to avoid contamination. We find r=23.5+-0.1
for the SN and r=22.9+-0.2 for the host galaxy, calibrated against
Pan-STARRS field stars.
We acknowledge the excellent support from the LBTO in particular D.
Thompson, and from the LBT-INAF staff, particularly S. Paiano, F.
Cusano, D. Paris and L. Cassar�� in obtaining and reducing these
observations.