GRB 220611A
GCN Circular 32595
Subject
GRB 220611A: Host galaxy redshift from VLT/X-shooter
Date
2022-09-27T15:22:02Z (3 years ago)
From
Benjamin Schneider at CEA <benjamin.schneider@cea.fr>
B. Schneider (CEA Paris-Saclay), D. B. Malesani (Radboud Univ. and DAWN/NBI),
J. P. U. Fynbo (DAWN/NBI), K. Wiersema (Univ. Lancaster), L. Izzo (DARK/NBI),
A. J. Levan (Radboud Univ.) report on behalf of the Stargate collaboration:
We observed the location of GRB 220611A (Cenko et al., GCN 32191;
Goad et al., GCN 32192; O���Connor et al., GCN 32203; Rastinejad et al.,
GCN 32208; Malesani et al., GCN 32222; Levan et al., GCN 32262) using the
X-shooter spectrograph mounted on the ESO VLT UT3 (Melipal). Our target was
the faint object visible in the archival optical images from the Legacy Survey,
coincident with the optical and X-ray afterglow, first noticed by
Rastinejad et al. (GCN 32208).
The observation was performed on 2022 September 23 (104 days after the GRB)
and consisted of 4x1200 s in the UVB and VIS arms and 8x600 s in the NIR arm.
A filter was adopted to block part of the K band which in return increases
the efficiency of the J and H bands, resulting in a wavelength coverage
between 3000 to 21000 AA.
In a preliminary reduction, we detect several strong emission lines that
we identify as Lyman-alpha, [O II] 3729, [O III] 4959 and [O III] 5007 at a
common redshift of z = 2.3608 +/- 0.0002. The [O II] 3726 and H-beta lines
are affected by sky lines and are consequently not clearly detected. H-alpha
falls outside the covered wavelength range.
This result is supported by a VLT/MUSE spectrum obtained on 2022 August 24,
covering the wavelength range 4800 to 9300 AA, which shows no emission nor
absorption features, consistent with the measured redshift from X-shooter.
The positional coincidence between our target and the optical and X-ray
afterglow suggests a physical association. Furthermore, our spectra show
that the archival counterpart is a star-forming galaxy, akin to a typical
long GRB host. Our observations bring thus evidence that the GRB was not
physically associated with the local, nearby galaxy MCG-06-10-007 at z = 0.049
(Cenko et al., GCN 32191), and their proximity is a chance coincidence.
We acknowledge expert support from the ESO staff in Paranal, in particular
Thomas Rivinius and Michael Abdul-Masih.
GCN Circular 32262
Subject
GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
Date
2022-06-24T18:10:44Z (3 years ago)
From
Daniele B Malesani at Radboud U <d.malesani@astro.ru.nl>
A. J. Levan (Radboud Univ.), D. B. Malesani (Radboud Univ. and
DAWN/NBI), B. P. Gompertz (Birmingham) report on behalf of a larger
collaboration:
The Chandra X-ray observatory imaged the X-ray afterglow of GRB 220611A
(Cenko et al., GCN 32191). Observations started on 2022 Jun 23.92 UT
(12.15 days after the GRB), using the ACIS-S instrument, for a total
exposure time of 15 ks.
We detect a single object consistent with the Swift X-ray position (Goad
et al., GCN 32192), with a total of ~30 source counts. Its coordinates
are (J2000):
RA = 04:26:03.57
Dec = -37:15:35.1
with an uncertainty of ~0.5". This position is consistent with the
optical and near-infrared source reported by Gemini-S (O���Connor et al.,
GCN 32203, 32217; Rastinejad et al., GCN 32208) and VLT (Malesani et
al., GCN 32222), as well as with the source seen in archival images from
the Legacy Survey. This detection thus cements the nature of this object
as the mutli-wavelength afterglow of GRB 220611A.
We thank the Chandra director, Pat Slane, for awarding discretionary
time to this project, and the observatory staff for rapidly planning and
scheduling these observations.
GCN Circular 32228
Subject
GRB 220611A: Continued Gemini Infrared Observations
Date
2022-06-19T21:39:00Z (3 years ago)
From
Brendan O'Connor at UMD <oconnorb@umd.edu>
B. O'Connor (UMD/GWU), E. Troja (U Tor Vergata/ASU), S. Dichiara (PSU),
S. B. Cenko (UMD/GSFC), report on behalf of a larger collaboration:
Additional target of opportunity observations of GRB 220611A
(Cenko et al. GCN 32191) were carried out with the FLAMINGOS-2
spectrograph mounted on the Gemini-South telescope. Observations
began at ~7.7 d in the Ks filter with a total exposure of 912 s.
We detect the GRB afterglow (O���Connor et al. GCNs 32203 and 32217,
Rastinejad et al. GCN 32208, Malesani et al. GCN 32222) with magnitude
Ks~21.8 AB mag calibrated against stars in the 2MASS catalog. Compared
to earlier Ks data (O���Connor et al. GCN 32203, Rastinejad et al. GCN
32208), the infrared counterpart���s temporal decay is consistent with the
decay observed in X-rays by Swift/XRT.
We thank the Gemini staff for rapid scheduling of these observations.
GCN Circular 32222
Subject
GRB 220611A optical counterpart
Date
2022-06-18T19:10:23Z (3 years ago)
From
Giovanna Pugliese at API/UvA <pugliese@astroduo.org>
D. B. Malesani (Radboud Univ. and DAWN/NBI), G. Pugliese (Amsterdam Univ. and Leiden Observatory), P. Schady (Univ. Bath), A. J. Levan (Radboud Univ.), B. P. Gompertz (Birmingham), report on behalf of the Stargate collaboration:
We observed the candidate counterpart (O'Connor et al., GCN 32203; Rastinejad et al., GCN 32208) of GRB 220611A (Cenko et al., GCN 32191) using the ESO VLT UT1 (Antu) equipped with the FORS2 imager. Observations were taken in twilight using the I filter, at an average airmass of 2.6, and with a delivered seeing of 1.9". The mean time of the observation (twenty 30-s images) was Jun 18.42 UT (6.67 days after the GRB).
The object noted by O'Connor et al. (GCN 32203) is detected in the stack of our data. Calibrating against three stars from the SkyMapper survey, we measure a preliminary magnitude of i = 23.0 +- 0.2 (AB).
Compared to the archival brightness r = 24.5 from the Legacy Survey (Rastinejad et al., GCN 32208), our measurement favors some transient contribution, consolidating the association of this object to GRB 220611A. Alternatively, the source could be very red, which would however be in contrast with the non-detection in the Legacy Survey z-band image.
We note that the observed magnitude is fainter by ~4.5 mag than what SN 1998bw would look like at z = 0.049, likely ruling out a traditional collapsar GRB in MCG-06-10-007. GRB 220611A might be a background event (consistent with the detection of a potential host galaxy in the Legacy Survey) or, speculatively, originate from a merger event, which would be more consistent with the offset and spectral type of MCG-06-10-007.
We acknowledge support with this difficult observation from the VLT staff at Paranal, in particular Cedric Ledoux and Joseph Anderson.
[Editor's Note: GRB Name corrected from GRB 221106A to GRB 220611A.]
GCN Circular 32217
Subject
GRB220611A: Gemini Optical Afterglow Confirmation
Date
2022-06-18T13:24:01Z (3 years ago)
From
Eleonora Troja at GSFC <eleonora.troja@nasa.gov>
B. O���Connor (UMD/GWU), E. Troja (U Tor Vergata/ASU) , S. Dichiara (PSU),
and S. B. Cenko (NASA/GSFC) report on behalf of a larger collaboration:
We carried out additional target of opportunity observations of GRB220611A
(Cenko et al.
GCN 32191) with the Gemini Multi Object Spectrograph (GMOS) mounted on the
Gemini-South
telescope. The observations began 5.7 d after the GRB trigger, and were
performed in
i-band for a total exposure of 540 s.
We detect the source reported by O���Connor et al. (GCN 32203) with magnitude
i~21 AB.
This source is not detected in archival images from the Dark Energy Survey
(Abbott et
al. 2021), and is likely the GRB afterglow. We determine that the X-ray,
optical,
and infrared data (O���Connor et al. GCN 32203, Rastinejad et al. GCN 32208)
can be
modeled by a power-law with spectral index beta~1.
Further observations are planned.
We thank the Gemini staff for rapid scheduling of these observations.
GCN Circular 32208
Subject
GRB 220611A: Gemini Ks counterpart detection
Date
2022-06-17T17:37:14Z (3 years ago)
From
Jillian Rastinejad at Northwestern Univ. <jillianrastinejad2024@u.northwestern.edu>
J. Rastinejad (Northwestern), A. J. Levan (Radboud), D. B. Malesani (Radboud and DAWN/NBI), B. P. Gompertz (Birmingham), W. Fong, C. D. Kilpatrick (Northwestern) report on behalf of a larger collaboration:
We observed the location of GRB 220611A (Cenko et al., GCN 32191) with the FLAMINGOS-2 instrument mounted on the Gemini-South 8-meter telescope on Cerro Pachon, Chile. At a mid-time of 2022 Jun 17.43 UT (~5.7 days post-burst), we obtained 48 x 11 s of K-band imaging at a median airmass of 2.15 and seeing of 1.1 arcsec. A K-band source is detected at the location reported by O'Connor et al. (GCN 32203). Based on calibration to 2MASS, we estimate a preliminary magnitude for the source of K_AB ~ 21.1 +/- 0.2 mag. Compared to the measurement reported by O'Connor et al. (K_AB = 20.0 +/- 0.3 mag), our value is indicative of fading, though we note that the strong, non-uniform background due to the nearby galaxy MCG-06-10-007 and the lack of a common set of calibrators prevent a definitive statement. Furthermore, the source is not detected in archival imaging from the VISTA Hemisphere Survey (VHS; Cross et al. 2012), from which we measure a limiting magnitude K_AB > 20.5 mag. If confirmed, the fading and the non-detection in the VHS images would indicate that this object is transient, thus likely associated with GRB 220611A.
We also note that a faint optical source is visible in r-band Legacy Source imaging (Dey et al. 2019) at the location reported by O'Connor et al. (GCN 32203). We measure a preliminary magnitude of r_AB ~ 24.5 +/- 0.3 mag for this source (again, uncertain due to the strong, non-uniform background). At present, it is not possible to discern if this source is associated with the z = 0.049 galaxy, or is a fainter, background galaxy.
Further observations are planned. We thank Jen Andrews, German Gimeno and Ricardo Salinas at Gemini for the rapid planning and execution of these observations.
GCN Circular 32203
Subject
GRB 220611A: Gemini South Infrared Detection
Date
2022-06-16T18:57:55Z (3 years ago)
From
Brendan O'Connor at UMD <oconnorb@umd.edu>
B. O'Connor (UMD/GWU), E. Troja (Tor Vergata), S. Dichiara (PSU),
on behalf of a larger collaboration:
We performed target of opportunity observations of GRB 220611A
(Cenko et al. GCN 32191) with the FLAMINGOS-2 spectrograph
mounted on the Gemini-South telescope. Observations were carried
out in the Ks filter with a total exposure of 260 s beginning at
3.7 d post-trigger.
We detect a faint source within the XRT position (Goad et al. 32192)
with magnitude Ks = 20.0+/-0.3 AB mag. The object is located at:
RA, DEC = 04:26:03.56, -37:15:34.97
with an uncertainty of 0.5". This source is offset by 6" and 13",
respectively, from two bright galaxies. The latter is located
at redshift z~0.049 (Cenko et al. GCN 32191). Further observations
are planned to determine whether the source is fading or if it
is dominated by the contribution from an underlying host galaxy.
We thank the staff of the Gemini Observatory, in particular
Steve Margheim and Joan Font-Serra, for rapid scheduling of
these observations. We thank Rodrigo Carrasco for carrying
out the observations.
GCN Circular 32201
Subject
GRB 220611A: Swift/UVOT Upper Limits
Date
2022-06-15T16:59:08Z (3 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220611A
153 s after the BAT trigger (Cenko et al., GCN Circ. 32191).
No optical afterglow consistent with the XRT position
(Cenko et al. GCN Circ. 32191) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 153 302 147 >19.5
u_FC 311 561 246 >19.1
white 153 926 245 >19.5
v 641 835 39 >17.0
b 566 759 39 >18.2
u 311 734 265 >19.1
w1 690 710 19 >17.7
m2 665 685 19 >17.9
w2 616 636 19 >18.7
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.033 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 32197
Subject
GRB 220611A: Swift-BAT refined analysis
Date
2022-06-13T22:36:11Z (3 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(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 220611A (trigger #1110090)
(Cenko et al., GCN Circ. 32191). The BAT ground-calculated position is
RA, Dec = 66.505, -37.265 deg which is
RA(J2000) = 04h 26m 01.2s
Dec(J2000) = -37d 15' 54.2"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 70%.
The mask-weighted light curve shows a weak pulse that starts at ~T0
and ends at ~T+60 s. There might be a possible precursor emission
(~ 5 sigma in the 15-350 keV image) from ~T-90 s to ~T-85 s.
T90 (15-350 keV) is 57.00 +- 12.37 sec (estimated error including
systematics).
The time-averaged spectrum from T+0.52 to T+61.52 sec is best fit
by a simple power-law model. The power law index of the time-averaged
spectrum is 1.87 +- 0.29. The fluence in the 15-150 keV band is
6.7 +- 1.3 x 10^-7 erg/cm2. All the quoted errors are at
the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1110090/BA/
GCN Circular 32195
Subject
Swift GRB 220611A: Global MASTER-Net observations report
Date
2022-06-12T13:10:39Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(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
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 220611A ( S. B. Cenko et al., GCN 32191) errorbox 55433 sec after notice time and 55505 sec after trigger time at 2022-06-12 09:26:56 UT, with upper limit up to 18.6 mag. The observations began at zenith distance = 74 deg. The sun altitude is -25.6 deg.
The galactic latitude b = -44 deg., longitude l = 240 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2003639
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
55596 | MASTER-OAFA | C | 180 | 18.0 |
56606 | MASTER-OAFA | C | 180 | 18.1 |
56950 | MASTER-OAFA | C | 180 | 18.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 32194
Subject
GRB 220611A: Swift-XRT refined Analysis
Date
2022-06-12T08:07:14Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), E. Ambrosi
(INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR),
J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), A.P.
Beardmore (U. Leicester) and S.B. Cenko report on behalf of the
Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 220611A (Cenko et al. GCN
Circ. 32191), from 133 s to 40.2 ks after the BAT trigger. The data
comprise 270 s in Windowed Timing (WT) mode (the first 10 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN Circ. 32192).
The late-time light curve (from T0+5.3 ks) can be modelled with a
power-law decay with a decay index of alpha=0.28 (+0.19, -0.21).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.31 (+/-0.06). The
best-fitting absorption column is 1.04 (+0.13, -0.12) x 10^21 cm^-2,
in excess of the Galactic value of 2.7 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.96 (+0.18, -0.08)
and a best-fitting absorption column consistent with the Galactic
value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.2 x 10^-11 (3.4 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.7 (+1.8, -0.0) x 10^20 cm^-2
Galactic foreground: 2.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.96 (+0.18, -0.08)
If the light curve continues to decay with a power-law decay index of
0.28, the count rate at T+24 hours will be 0.045 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x
10^-12 (1.6 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01110090.
This circular is an official product of the Swift-XRT team.
GCN Circular 32192
Subject
GRB 220611A: Enhanced Swift-XRT position
Date
2022-06-11T20:54:10Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 496 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 220611A, 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 = 66.51464, -37.26019 which is equivalent
to:
RA (J2000): 04h 26m 3.51s
Dec (J2000): -37d 15' 36.7"
with an uncertainty of 2.4 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 32191
Subject
GRB 220611A: Swift detection of a burst
Date
2022-06-11T18:36:01Z (3 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
S. B. Cenko (GSFC), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC),
V. D'Elia (SSDC & INAF-OAR), J.D. Gropp (PSU), J. A. Kennea (PSU),
S. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 18:01:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220611A (trigger=1110090). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 66.526d, -37.289d which is
RA(J2000) = 04h 26m 06s
Dec(J2000) = -37d 17' 20
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). Due to a telemetry gap, the BAT onboard
lightcurve is not immediately available. However, the triggering
algorithm found the source in an 8 second image, indicating a
long GRB.
The XRT began observing the field at 18:04:20.4 UT, 149.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 66.51418, -37.25899
which is equivalent to:
RA(J2000) = 04h 26m 03.40s
Dec(J2000) = -37d 15' 32.4"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 113 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. We cannot determine whether the source
is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.66
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 152 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.033.
We note that this source location is ~15 arcsec from the line of sight
to the galaxy MCG-06-10-007, which is described in Simbad
as an S0 galaxy, B=16.3, z~0.049, angular size 18"x16".
Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov).
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/)