ZTF23aaoohpy
GCN Circular 34022
Subject
ZTF23aaoohpy/AT2023lcr: Zwicky Transient Facility discovery of a fast fading red transient
Date
2023-06-19T17:12:17Z (2 years ago)
From
Igor Andreoni at JSI/UMD/NASA <igor.andreoni@gmail.com>
Vishwajeet Swain (IITB), Igor Andreoni (JSI/UMD/NASA-GSFC), Michael Coughlin (UMN), Harsh Kumar (IITB), Anirudh Salgundi (IITB) on behalf of the ZTF Collaboration
We report the discovery of the fast fading transient candidate ZTF23aaoohpy/AT2023lcr with the Zwicky Transient Facility (ZTF, Bellm et al. 2019, Graham et al. 2019) at coordinates:
RA = 16:31:37.40 (247.9058524d)
Dec = +26:21:58.35 (26.3662079d)
ZTF23aaoohpy was first detected on 2023-06-18 06:36:27 UT at g = 19.658 +- 0.141 mag (AB). ZTF23aaoohpy faded by about ~1.0 magnitudes per day in both g- and r-band. The non-detection limiting magnitude of 21.1 was measured in g-band on 2023-06-17 09:39:58 UT, which is about 23 hours before the first detection. There is no pre-detection at the transient location in the last 80 images of the field previously acquired by the ZTF survey. ZTF photometry is reported in the following table:
----------------------------------
MJD | mag AB
----------------------------------
60113.275313 | g = 19.66 +- 0.14
60114.279398 | g = 20.67 +- 0.27
60113.337488 | r = 19.37 +- 0.10
60114.341065 | r = 20.38 +- 0.19
----------------------------------
Extinction along the line of sight is small, with E(B-V)=0.05 mag. The transient is located at high Galactic latitude b=41.25 deg. There is no cataloged source at the transient location in deep Legacy Survey DR10 and Pan-STARRS (Chambers et al., 2016) archival images.
Follow-up observations are encouraged.
ZTF23aaoohpy was discovered by the ''ZTF Realtime Search and Triggering'' project (ZTFReST; Andreoni & Coughlin et al., 2021) within the ZTF Collaboration.
Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-2034437 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, and IN2P3, France. Operations are conducted by COO, IPAC, and UW.
GCN Circular 34023
Subject
ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
Date
2023-06-19T19:52:34Z (2 years ago)
From
Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>
B. Gompertz, K. Ackley, G. Ramsay, J. Lyman, D. O’Neill, A. Levan, K. Ulaczyk, M. Dyer, T. Killestein, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, D. Pollacco, K. Noysena, L. Nuttall, E. Pallé, report on behalf of the GOTO collaboration:
We report on observations of the fast fading transient candidate ZTF23aaoohpy/AT2023lcr (Swain et al, GCN 34022). The field was covered three times by the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2021) between 2023-06-17 and 2023-06-18. We detect the reported transient in an observation taken at 01:27:41 UT on 2023-06-18 (5.1 hours before the ZTF discovery) with a magnitude of 18.77+/- 0.06 in the GOTO L-band (400 – 700nm). The source was not detected in the previous epoch at 23:50:30 UT on 2023-06-17 to a 5-sigma limiting magnitude of L > 20.3. The measured rise is therefore > 1.5 magnitudes in 1h45m, and constrains the onset to between these two epochs. The GOTO L-band is approximately g+r, and therefore taking the first ZTF epoch of detection to be L ~ 19.5, our detection implies a fading rate of ~0.75 mag over 0.2 days - significantly faster than the 1mag/day between the two ZTF epochs.
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and not corrected for Galactic extinction.
GOTO (https://goto-observatory.org) is a network of telescopes operated at the Roque de los Muchachos Observatory on La Palma, Spain and Siding Spring Observatory in NSW, Australia; on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), University of Turku, University of Portsmouth, University of Manchester and the Instituto de Astrofisica de Canarias (IAC)
GCN Circular 34025
Subject
ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
Date
2023-06-19T21:18:43Z (2 years ago)
From
Vishwajeet Swain at IIT Bombay <vishwajeet.s@iitb.ac.in>
H. Kumar, V. Swain, A Salgundi, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with 0.7m GROWTH-India Telescope (GIT). We obtained multiple frames of 300 sec each in the g', r' and i' band. We detected the source in our stacked images and got the following photometric results:
----------------------------------------------------------------------
JD (mid) | Filter | Exposure (s) | Magnitude (AB) |
----------------------------------------------------------------------
2460115.234132 | r' | 10 x 300 | 20.67 +/- 0.07 |
2460115.279899 | g' | 7 x 300 | 21.37 +/- 0.15 |
2460115.306489 | i' | 5 x 300 | 20.70 +/- 0.17 |
----------------------------------------------------------------------
A comparison of GIT photometry with ZTF (Swain et al, GCN 34022) and GOTO (Gompertz et al, GCN 34023) observations, we confirm that the candidate is decying fast and is redder in color.
The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular 34030
Subject
ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
Date
2023-06-20T00:15:55Z (2 years ago)
From
Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>
T. Adami (ENS/Saclay, LAM/Pytheas/AMU), C. Adami (LAM/Pytheas/AMU),
D. Turpin, E. Le Floc'h (CEA Paris-Saclay), J. T. Palmerio,
S. D. Vergani (GEPI, Obs. de Paris), B. Schneider (MIT),
S. Basa (LAM), D. Götz (CEA Paris-Saclay), report on behalf of a
larger collaboration:
We observed the field of ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022,
Gompertz et al., GCN34023, Kumar et al., GCN34025)using the T193cm
and T120cm telescopes at Observatoire de Haute-Provence (France)
respectively equipped with the MISTRAL spectro-imager and the T120 CCD camera.
A total of 8 exposures were obtained in the imaging mode of MISTRAL in
the r-band filter (1x360s +7x600s). Observations were made
from 2023-06-19 21:13:47.60 UT to 2023-06-19T22:37:40.86 UT
(mid time ~1.85d after the T_GOTO = 2023-06-18 01:27:41
(Gompertz et al., GCN34023)).
A total of 16 exposures were also obtained with the T120 CCD camera
in the R-band filter (1x300s +8x450s, mid time ~ T_GOTO+1.83d)
and V-band (7x600s, mid time ~ T_GOTO+1.88d).
In the coadded images, we measured the following magnitudes:
----------------------------------------------------------------------
JD (mid) | Telescope | Filter | Exposure (s) | Magnitude (AB) |
----------------------------------------------------------------------
2460115.3875 | OHP-T120 | R | 3900 | 20.70 +/- 0.12 |
2460115.413706 | OHP-T193/MISTRAL | r' | 4560 | 20.84 +/- 0.04 |
2460115.440972 | OHP-T120 | V | 4200 | 20.85 +/- 0.07 |
----------------------------------------------------------------------
The photometric calibration was performed using nearby stars
from the PS1 catalog and the magnitudes are not corrected for
Galactic extinction.
Our measurements confirm that the source is fading at a mag rate ~ 0.9 mag/day
compared to the last r magnitude reported by ZTF (Swain et al., GCN 34022).
The red color of this transient g-r ~ 0.3 and its confirmed fast-fading evolution
are consistent with a Gamma-ray Burst afterglow emission.
We strongly encourage spectroscopic follow-up of this source in order to identify
its astrophysical origin.
Additional I-band follow-up observation will be performed at OHP this night.
We acknowledge the excellent support from Observatoire de Haute-Provence,
in particular Yoann Degot Longhi for the MISTRAL observations, Gavin Coleman
the observer using the T193/SOPHIE instrument who allowed us to perform
these ToO observations as well as Pascal Gallais, Antoine Claret and
Matthias Tornay for the T120 observations.
GCN Circular 34031
Subject
ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
Date
2023-06-20T00:47:30Z (2 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
Daniel A. Perley (LJMU), Maggie Li (Cornell), and Anna Y. Q. Ho (Cornell) report:
We obtained Liverpool Telescope follow-up imaging observations of the fast optical transient ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) on the night of 2023-06-19. Observations were conducted in g/r/i filters between UT 22:15-22:29 and in u/r/z filters between 22:47-23:05.
The source is well-detected in the g, r, i, and z filters. We measure photometry of:
MJD magnitude
60114.92765 g = 21.32 +/- 0.08
60114.93103 r = 20.88 +/- 0.06
60114.93440 i = 20.68 +/- 0.06
60114.94962 r = 21.04 +/- 0.06
60114.95300 z = 20.47 +/- 0.10
60114.95733 u > 21.3
The photometry is well-fit by a power-law with spectral index (F_nu ~ nu^beta) of beta ~ -1.2, consistent with GRB afterglows.
GCN Circular 34040
Subject
ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
Date
2023-06-20T16:31:09Z (2 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Q. Jiang, S.Y. Fu, Z.P. Zhu, X. Liu, T.H. Lu, D. Xu (NAOC) report:
We observed the field of ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) using the 2.16m telescope located at Xinglong, Hebei, China, equipped with the BFOSC camera. Observations started at 12:39:19 UT on 2023-06-20, i.e., 2.47 day after the T_GOTO=2023-06-18 01:27:41 (Gompertz et al., GCN34023), and 8x300 s frames were obtained in the R-band.
The previously reported optical transient (e.g., Swain et al., GCN 34022, Gompertz et al., GCN34023, Kumar et al., GCN34025, Adami et al., GCN34030, Perley et al., GCN34031) is detected in our coadded image with m(R) = 21.34 +/- 0.14 at 60115.5432 (MJD), calibrated with the nearby Pan-STARRS field.
We thank the great support of the Xinglong-2.16m staff.
GCN Circular 34041
Subject
ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
Date
2023-06-20T18:20:09Z (2 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
Daniel A. Perley (LJMU), Igor Andreoni (JSI/UMD/NASA-GSFC), Kareem El-Badry (CIT), Ilaria Caiazzo (CIT), Michael Coughlin (UMN), Mansi Kasliwal (CIT), and Zach Vanderbosch (CIT) report:
We observed the fast optical transient ZTF23aaoohpy/ATLAS23msn/AT2023lcr (Swain et al., GCN 34022; Gompertz et al., GCN34023; Kumar et al., GCN34025; Perley et al, GCN 34031; Fulton et al., AstroNote 2023-179) with the Low Resolution Imaging Spectrometer (LRIS) at W. M. Keck Observatory. Observations started on 2023 June 20 at 07:22 UT. The exposure time was 2x1200s and 3x800s in the blue and red arms of LRIS, respectively. Observations employed the 600/4000 blue grism and 600/7500 red grating, providing continuous wavelength coverage from 3140 to 8784 Angstroms. Data were reduced using LPipe (Perley, 2019).
The spectrum shows a simple continuum, well-fit by a simple power-law of f_lamba~lambda^-1. The signal-to-noise ratio is about 20 per resolution element (although lower blueward of 4000 Angstroms). We detect clear (but weak) absorption lines at observer-frame wavelengths of 5688 and 5683 Angstroms which we attribute to the redshifted MgII(2796,2803) doublet at z=1.0272. Weak absorption from FeII 2344 and FeII 2383 at a consistent redshift is also detected. We also detect a possible intervening MgII absorber at z=0.7795. No other lines are apparent in the spectrum.
Based on this information, we propose z=1.0272 as the redshift of this event. While strictly this redshift is only a lower limit, the absence of any higher-redshift absorption features suggests that a higher-redshift origin is unlikely. The lack of Lyman-alpha absorption over the spectral range imposes a redshift upper limit of z<1.6. In either case, the spectroscopy confirms this to be an intrinsically very luminous, fast-rising event with a power-law SED characteristic of synchtrotron radiation, similar in nature to GRB afterglows.
GCN Circular 34043
Subject
AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
Date
2023-06-20T19:21:32Z (2 years ago)
From
Ting-Wan Chen at MPE <janet.chen@astro.su.se>
T.-W. Chen (TUM), S. Yang (HNAS), A.-L. Tsai, W.-P. Chen, W.-J. Hou, H.-Y. Hsiao, C.-C. Ngeow, C.-S. Lin, Y.-C. Pan, H.-C. Lin, and J.-K. Guo (all NCUIA) report:
We observed the field of AT 2023lcr, an orphan transient discovered by the ATLAS survey as ATLAS23msn (Tonry et al. TNS Astronomical Transient Report No. 180429; Fulton et al. AstroNote 2023-179). Its fast fading and red nature was identifed and reported by Swain et al. (GCN 34022) as ZTF23aaoohpy.
We used the 40cm SLT and 1-m LOT at Lulin Observatory, Taiwan to obtain r and g-band images of AT 2023lcr, as part of the Kinder collaboration (Chen et al., AstroNote 2021-92).
The first SLT epoch of observations started at 18:22 UT on 19 of June 2023 (MJD = 60114.765), 1.36 days after the ATLAS discovery. The images were combined from 18 frames with a 300-second exposure time for the r band, taken under seeing conditions of an average of 1.64" and at a median airmass of 2.08. For the LOT observations, the first epoch started later at 19:29 UT on 19 of June 2023 (MJD = 60114.812). The images were combined from 8 frames with a 300-second exposure time for the g band, taken under seeing conditions of an average of 1.50" and at a median airmass of 2.95. We used the Kinder pipeline (Yang et al. A&A 646, A22) to measure the PSF photometry of AT 2023lcr after template subtraction using the SDSS images. We obtained the following preliminary magnitudes (in the AB system):
g = 21.41 +/- 0.16 mag, and
r = 20.94 +/- 0.14 mag.
The given limit is derived based on calibrating against SDSS field stars and is not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.04 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
We collected the light curve evolution of AT 2023lcr from all relevant photometric reports (Swain et al., GCN 34022; Gompertz et al. GCN 34023; Kumar et al., GCN 34025; Fulton et al., AstroNote 2023-179; Adami et al. GCN 34030; Perley et al. GCN 34031; Jiang et al., GCN 34040; Fulton et al., GCN 34042) to date, and the light curve plot can be found in the following link (https://photos.app.goo.gl/QpWzJse6NMozERjZ7). The magnitudes obtained from Lulin Observatory are in agreement with the mentioned reports and further support the evidence for a power-law decay in GRB afterglows. Moreover, we have noticed a potential 'plateau' in the g-band light curve, which occurs between the Lulin and PanSTARRS observations.
GCN Circular 34047
Subject
ZTF23aaoohpy/AT2023lc: Mondy optical observations
Date
2023-06-21T09:26:11Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI, HSE), E. Klunko (ISTP), A. Pozanenko (IKI), N. Pankov (HSE) report on behalf of GRB IKI FuN:
We observed the field of ATLAS23msn/ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with AZT-33IK telescope of Mondy observatory in R-filter on 2023-06-20 starting (UT) 15:34:09 (mid exposure time is ~2.4 days after the ZTF discovery). We detect the optical counterpart (Gompertz et al., GCN34023; Kumar et al., GCN34025; Adami et al., GCN 34030; Perley et al, GCN 34031; Jiang et al., GCN 34040; Perley et al., GCN 34041; Fulton et al., 34042; Chen et al., GCN 34043). Preliminary photometry of a stacked image is following
Date UT start MJD Exp. Filter OT Err. UL(3sigma)
(mid exposure) (s)
2023-06-20 15:34:09 60115.66607639 25*120 R 21.42 0.17 22.4
The photometry is based on nearby SDSS-DR12 stars.
SDSS-DR12
RA DEC R(Lupton transformations)
16:31:20.4491016 +26:24:03.644928 18.124
16:31:41.2384008 +26:20:23.267580 17.545
16:31:32.6899656 +26:20:16.058832 18.238
16:31:31.3849992 +26:19:27.712488 18.804
GCN Circular 34049
Subject
ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
Date
2023-06-21T11:43:05Z (2 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and S. R. Oates (U. Birmingham) report on behalf of the Swift/UVOT team:
Follow-up observations of the optical fast transient ATLAS23msn/ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022; Gompertz et al., GCN 34023; Kumar et al., GCN 34025; Adami et al., GCN 34030; Perley et al., GCN 34031; Jiang et al., GCN 34040; Perley et al., GCN 34041; Fulton et al., 34042; Chen et al., GCN 34043, Belkin et al., GCN 34047) were carried out with the Neil Gehrels Swift Observatory between 2023-06-20 12:57:02 UT and 2023-06-20 14:54:56 UT, in which a source was detected by the XRT (Adreoni, GCN 34044).
A source was also detected in the Swift UVOT data in the UVM2 filter at the position given by Swain et al., (GCN 34022). Possible detections are also obtained in the U, UVW1 and UVW2 filters but at a significance below 3 sigma. Preliminary tentative detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the summed exposures are:
FILTER EXP(s) MAG Significance of Upper Limits (3o)
Detection
v 157 >19.6
b 157 >20.6
u 157 20.6 ± 0.5 2.1 sigma >20.1
w1 315 20.4 ± 0.5 2.1 sigma >20.0
m2 1489 20.8 ± 0.3 3.9 sigma
w2 629 21.0 ± 0.4 2.5 sigma >20.7
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998)
GCN Circular 34051
Subject
ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
Date
2023-06-21T17:50:27Z (2 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
Konus-Wind (KW) was observing the whole sky between the last
GOTO non-detection (2023-06-17 23:50:30 UTC, hereafter T1;
Gompertz at al., GCN Circ. 34023) and the first GOTO detection
(2023-06-18 01:27:41 UTC, hereafter T2; Gompertz at al., GCN Circ. 34023)
of ZTF23aaoohpy/AT2023lcr/ATLAS23msn (Swain et al., GCN Circ. 34022;
Tonry et al. TNS Astronomical Transient Report No. 180429).
No triggered or waiting-mode KW GRBs were detected during the
interval from T1 to T2. The closest waiting-mode GRBs were observed
~6.5 hours before T1 and ~2.3 hours after T2.
For the interval from T1 to T2, we estimate an upper limit (90% conf.)
on the 20 - 1500 keV fluence to 6.5x10^-7 erg/cm^2 for a burst lasting
less than 2.944 s and having a typical KW short GRB spectrum
(an exponentially cut off power law with alpha =-0.5 and Ep=500 keV).
For a typical long GRB spectrum (the Band function with alpha=-1,
beta=-2.5, and Ep=300 keV), the corresponding limiting peak flux
is 1.8x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale).
All the quoted values are preliminary.
GCN Circular 34052
Subject
ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
Date
2023-06-21T20:42:48Z (2 years ago)
From
Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it>
S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy), G. Bonnoli (INAF-OAB) report:
We observed the field of the fast red optical transient ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022; Gompertz et al., GCN 34023; Kumar et al., GCN 34025; Adami et al., GCN 34030; Perley et al., GCN 34031; Jiang et al., GCN 34040; Perley et al., GCN 34041; Fulton et al., 34042; Chen et al., GCN 34043, Belkin et al., GCN 34047; A. A. Breeveld, GCN 34049) with the automatic 0.53m Ritchey-Chretien telescope + U47 detector at Montarrenti Observatory (Siena, Italy, IAU code C88).
The observations were started under mediocre weather conditions at 2023-06-19 21:54:09 UT (approximately 5 hours after notice) stacking a sets of R and I-band CCD images.
The OT was detected at the following position:
RA (J2000.0) 16h 31m 37.42s +/-0.17
Decl. (J2000.0) +26° 21' 58.00" +/-0.16
Preliminary photometry is obtained using nearby PanSTARRS stars as follows:
MJD Filter Mag. Err.
60114.91576 R 20.53 +/-0.20
60114.91631 I 20.02 +/-0.19
Measures are not corrected for galactic dust extinction.
Montarrenti Observatory (IAU code C88) is a public observatory located close to the homonym medieval castle near Siena - Italy managed by the local amateur astronomer association (Unione Astrofili Senesi). The main instrument is an automated and remoted Ritchey-Chretien telescope D=0.53m - f/8.7 equipped with U47 back-illuminated camera. The observatory is devoted to supernovae search, GRB afterglow detection and photometric follow-up of blazars
GCN Circular 34060
Subject
ZTF23aaoohpy/AT2023lcr: SAO RAS observations
Date
2023-06-22T13:17:37Z (2 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), S. Belkin (IKI RAS,
HSE), A. Pozanenko (IKI RAS), report on behalf of a larger
collaboration.
We observed the field of the fast red optical transient
ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with the 1-m
telescope of SAO RAS Zeiss-1000/CCD-photometer. We obtained 8 x 300
sec images in Rc band on 2023.06.21, 21:06:39--21:52:39 UT, 3.8347
days after GOTO detection (Gompertz et al., GCN 34023) or 3.7432 days
after ZTF detection (Swain et al., GCN 34022).
The OT (Swain et al., GCN 34022; Gompertz et al., GCN 34023; Kumar et
al., GCN 34025; Adami et al., GCN 34030; Perley et al., GCN 34031;
Jiang et al., GCN 34040; Perley et al., GCN 34041; Fulton et al., GCN
34042; Chen et al., GCN 34043, Belkin et al., GCN 34047; Breeveld, GCN
34049; Leonini et al., GCN 34052) is clearly detected in the stacked
frame with the brightness of R = 21.51 +/- 0.09 (based on stars
mentioned in Belkin et al., GCN 34047).
GCN Circular 34077
Subject
ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
Date
2023-06-24T19:39:55Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI, HSE), I. Sokolov (KIAM), I. Nikolenko (INASAN), A. Pozanenko (IKI), N. Pankov (HSE) report on behalf of GRB IKI FuN:
We observed the field of ATLAS23msn/ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with Zeiss-1000 telescope of Koshka observatory in R-filter on 2023-06-20 and 2023-06-23. We detect the optical counterpart (Gompertz et al., GCN34023; Kumar et al., GCN34025; Adami et al., GCN 34030; Perley et al, GCN 34031; Jiang et al., GCN 34040; Perley et al., GCN 34041; Fulton et al., 34042; Chen et al., GCN 34043; Belkin et al., GCN 34047; Breeveld, GCN 34049; Leonini et al., GCN 34052; Moskvitin et al., GCN 34060) on 2023-06-20 and obtained an upper limit on 2023-06-23. Preliminary photometry of a stacked images is following
Date UT start MJD Exp. Filter OT Err. UL(3sigma)
(mid exposure) (s)
2023-06-20 19:14:22 60115.83567130 49*120 R 21.31 0.18 22.2
2023-06-23 18:43:28 60118.80657407 38*120 R n/d n/d 21.7
The photometry is based on nearby SDSS-DR12 stars.
SDSS-DR12
RA DEC R(Lupton transformations)
16:31:20.4491016 +26:24:03.644928 18.124
16:31:41.2384008 +26:20:23.267580 17.545
16:31:32.6899656 +26:20:16.058832 18.238
16:31:31.3849992 +26:19:27.712488 18.804
GCN Circular 34078
Subject
ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
Date
2023-06-25T08:21:06Z (2 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), S. Belkin (IKI RAS,
HSE), A. Pozanenko (IKI RAS), report on behalf of a larger
collaboration.
We observed the field of the fast red optical transient
ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with the 1-m
telescope of SAO RAS Zeiss-1000/CCD-photometer on June, 22 and 23. We
have obtained 10 x 300 sec in Rc band during each night.
The OT (Swain et al., GCN 34022; Gompertz et al., GCN 34023; Kumar et
al., GCN 34025; Adami et al., GCN 34030; Perley et al., GCN 34031;
Jiang et al., GCN 34040; Perley et al., GCN 34041; Fulton et al., GCN
34042; Chen et al., GCN 34043, Belkin et al., GCN 34047; Breeveld, GCN
34049; Leonini et al., GCN 34052; Moskvitin et al., GCN 34060, Belkin
et al., GCN 34077) is clearly detected in the stacked frames.
Preliminary results are as following.
Date UT-start MJD_mid t-T0 R_mag
2023-06-22 22:43:06 60117.96396 4.68865 21.68 +/- 0.14
2023-06-23 21:14:21 60118.91196 5.63665 22.12 +/- 0.08
Photometry is based on stars mentioned in Belkin et al.(GCN 34047,
34077) and Moskvitin et al. (GCN 34060). t-T0 is given in days after
the ZTF discovery (Swain et al., GCN 34022).
The light curve of the source has a shallow decay at least between
MJD=60616 and MJD=60618, and then the decay becomes significantly
steeper between MJD=60618 and MJD=60619.
GCN Circular 34079
Subject
INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
Date
2023-06-25T15:10:21Z (2 years ago)
From
Volodymyr Savchenko at ISDC, University of Geneva; LASTRO, EPFL <volodymyr.savchenko@unige.ch>
Volodymyr Savchenko (ISDC, University of Geneva; LASTRO, EPFL), Carlo Ferrigno (ISDC, University of Geneva), Antonio Martin-Carrillo (UCD), Sandro Mereghetti (IASF-Milano, INAF)
Using INTEGRAL serendipitous all-sky observations we searched for GRB associated with ZTF23aaoohpy/AT2023lcr (GCN #34022).
Between last non-detection at 2023-06-17T23:50:30 (T1) and first detection 2023-06-18T01:27:41 (T2) by GOTO (GCN #34023) INTEGRAL was observing the whole sky while maintaining stable attitude, and ZTF23aaoohpy/AT2023lcr was at an offaxis angle from 77.1 to 78.7 deg. This orientation implies optimal response of SPI-ACS and reduced response of other INTEGRAL all-sky instruments.
Background conditions were stable during the time interval of interest, with excess variance of 1.2 (1 s timescale). The background is also near its long-term minimum, typical for this phase of solar cycle.
No IBAS triggers occurred between T1 and T2. Following [1] we performed an offline-search for any GRB-like events between T1 and T2. In this time interval we did not find any relevant excesses.
We set a 3-sigma upper limit on the 75-2000 keV fluence of 1.7e-07 erg/cm^2 for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV). For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~1.5e-07 (5.6e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
In addition, the location of ZTF23aaoohpy/AT2023lcr was serendipitously in FoV of INTEGRAL pointing instruments during slew between 2023-06-18T05:25:38 (T2+3.9 h) and 2023-06-18T05:35 (T2+4.1 h). Using collimating properties of IBIS/ISGRI telescope, we set an rough upper limit on average flux in this time interval at the level of 1.9e-10 erg/cm2/s (28-80 keV energy range).
All the quoted values are preliminary.
SPI-ACS lightcurve for this event can be obtained through MMODA: https://www.astro.unige.ch/mmoda/?T1=2023-06-17T23:50:30&T2=2023-06-18T01:27:41&T_format=isot&data_level=ordinary&instrument=spi_acs&product_type=spi_acs_lc&time_bin=2&time_bin_format=sec
[1] Savchenko+ 2012, A&A
GCN Circular 34102
Subject
ZTF23aaoohpy /AT2023lcr: TNG NIR detection
Date
2023-06-28T14:15:11Z (2 years ago)
From
Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com>
R. Brivio, M. Ferro, P. D’Avanzo (INAF-OAB), D. B. Malesani (U. Radboud and DAWN/NBI), A. Melandri (INAF-OAB, INAF-OAR),
C. Padilla-Torres, A. Harutyunyan (INAF-TNG) on behalf of the CIBO collaboration report:
We observed the field of ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with the Italian 3.6m TNG telescope equipped with
the near-infrared camera NICS. A series of images were obtained with the J and K filters on 2023-06-22 from 03:10:54 UT to 04:32:57 UT
(i.e. at a mid time of about 60117.16 MJD).
At the position of the previously reported optical transient (e.g., Swain et al., GCN 34022, Gompertz et al., GCN 34023, Kumar et al.,
GCN 34025, Adami et al., GCN 34030, Perley et al., GCN 34031, Jian et al., GCN 34040) we clearly detect a source in both J and K filters.
From preliminary photometry we derive K ~ 18.8 mag (Vega; calibrated against the 2MASS catalogue), not corrected for Galactic extinction.
GCN Circular 34121
Subject
ZTF23aaoohpy/AT2023lcr: LBT observations
Date
2023-06-29T12:32:55Z (2 years ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
A. Rossi, E. Maiorano, E. Palazzi (INAF-OAS), D. B. Malesani (U. Radboud and DAWN/NBI), A. Melandri (INAF-OAB, INAF-OAR), report on behalf of the CIBO collaboration:
We observed the field of the fast red optical transient ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022; Gompertz et al., GCN 34023; Kumar et al., GCN 34025) with the LBC camera mounted on LBT (Mt Graham, AZ, USA) on 2023-06-23 in u’g’r’z’ bands at approximately 4:30 UT. A second observation was obtained on 2023-06-26 at 08:30 UT in g’r’z’ bands. Both observations were performed under good weather conditions.
We detect the optical transient in all bands and epochs and we measure the following preliminary AB magnitudes for the first observation:
r’= 22.5 +/- 0.1
calibrated against SDSS field stars, and not corrected for the foreground Galactic extinction.
We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly D. Thompson, D. Gonzalez Huerta, F. Cusano and D. Paris, in obtaining these observations.
GCN Circular 34125
Subject
AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
Date
2023-06-30T21:24:44Z (2 years ago)
From
Anna Y Q Ho at Cornell University <ayh24@cornell.edu>
Anna Y. Q. Ho (Cornell) and Daniel A. Perley (LJMU) report on behalf of a larger collaboration:
In an observation beginning at 03:35 on 29 June UT, we observed the location of the extragalactic fast optical transient AT2023lcr (Swain et al. GCN Circ. 34022; Fulton et al. GCN Circ. 34042) using the Atacama Large Millimeter/sub-millimeter Array (ALMA) in Band 3 (100 GHz) under excellent weather conditions. A counterpart was detected with a preliminary peak flux density of 0.17 mJy, at high significance (10-sigma).
Data were obtained under Program ID 2022.A.00025.T. We thank the ALMA staff for rapidly approving and executing our observations.
GCN Circular 34145
Subject
ZTF23aaoohpy/AT2023lcr: AMI-LA radio detection
Date
2023-07-05T18:55:59Z (2 years ago)
From
Assaf Horesh at Hebrew U, Jerusalem <assafh@mail.huji.ac.il>
Assaf Horesh (HUJI), Itai Sfaradi (HUJI), Lauren Rhodes (Oxford), Joe Bright (Oxford), Rob Fender (Oxford), Dave Green (Cambridge), David Titterington (Cambridge)
We report the detection of radio emission from the fast fading red transient ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) using the AMI-LA telescope.
We observed the field of AT 2023lcr with the Arcminute Microkelvin Imager –Large Array (AMI-LA) for 4 hours on the 2023-06-21, with a central frequency of 15.5 GHz. The flux standard 3c286 was used to calibrate the bandpass response and flux scale of the AMI-LA and J1613+3412 was used as an interleaved complex gain calibrator.
A point source is detected in the AMI-LA image at RA = 16:31:37.30 +/- 0.06 s, Dec = +26:22:01.0 +/- 3.0 arcsec, consistent with the reported position of AT 2023lcr. The source is detected at a flux density of 0.50 +/- 0.05 mJy.
We plan to perform follow-up observations with the AMI-LA, and encourage further high cadence multi frequency radio observations with other facilities.
We thank the staff of MRAO for scheduling and performing this observation.
GCN Circular 34158
Subject
ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
Date
2023-07-07T10:33:38Z (2 years ago)
From
Vishwajeet Swain at IIT Bombay <vishwajeet.s@iitb.ac.in>
H. Kumar (IITB), V. Swain (IITB), G. C. Anupama (IIA), S. Barway (IIA), V. Bhalerao (IITB), D.K. Sahu (IIA), R.S. Teja (IIA), R. Gupta (ARIES), K. Mishra (ARIES), D. Panchal (ARIES), S.B. Pandey (ARIES):
We observed ZTF23aaoohpy/AT2023lcr (Swain et al., GCN 34022) with the 2.0m Himalayan Chandra Telescope (HCT) of the Indian Astronomical Observatory (IAO). We obtained exposures in the SDSS r' filter. We detected the source in our stacked images and got the following photometric result:
-------------------------------------------------------------------
JD (mid) | Exposure (sec) | Filter | Magnitude (AB) |
-------------------------------------------------------------------
2460120.325395 | 8 x 300 | r' | 22.74 +/- 0.18 |
-------------------------------------------------------------------
The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
These observations were carried out under the ToO program HCT-2023-C2-P15. We thank the HCT staff for their support during the observations. The Indian Astronomical Observatory is operated by the Indian Institute of Astrophysics, Bengaluru, India.
GCN Circular 34370
Subject
ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
Date
2023-08-08T15:51:10Z (2 years ago)
From
Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo@ucd.ie>
Via
Web form
A. Martin-Carrillo (UCD), B. Schneider (MIT), T. Laskar (Utah), B. P. Gompertz (U. Birmingham), D. B. Malesani (Radboud and DAWN/NBI), A. de Ugarte Postigo (OCA/CNRS), A. J. Levan (Radboud), G. Finneran (UCD), J.F. Agui Fernandez (IAA-CSIC), C.C. Thoene (ASU-CAS), V. D'Elia (ASI-SSDC and INAF-OAR) and L. Izzo (INAF-OACN and DARK/NBI) report on behalf of a larger collaboration:
We obtained photometric observations of the orphan GRB afterglow ZTF23aaoohpy/AT2023lcr (Andreoni et al., GCN 3402; Swain et al., GCN 34022; Kumar et al., GCN 34025; Adami et al., GCN 34030; Perley et al., GCN 34031; Jiang et al., GCN 34040; Chen et al., GCN 34043) with the James Webb Space Telescope on 7 August 2023 (DDT program 4554, PI Martin-Carrillo). This was about 50.6 days after the likely explosion epoch (Gompertz et al., GCN 34023). Observations were obtained with the NIRCam instrument in the F115W, F150W, F277W, and F356W filters.
At the location of the optical/NIR transient, we detect a point-like source in all four bands, with F115W(AB) ~ 25.48 +/- 0.20. A fainter, extended source is observed about 0.5" to the S-W, which could be the host galaxy of AT 2023lcr.
These observations are in excess of the expected power-law decay of the GRB afterglow and are consistent with a supernova component.
Further analysis and observations are ongoing.
We thank the staff of STScI for their work to get these observations rapidly scheduled, in particular Alison Vick, Tony Keyes, Mario Gennaro and Armin Rest.
GCN Circular 34385
Subject
ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
Date
2023-08-12T18:14:52Z (2 years ago)
From
Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo@ucd.ie>
Via
Web form
A. Martin-Carrillo (UCD), A. J. Levan (Radboud), A. de Ugarte Postigo (OCA/CNRS), L. Izzo (INAF-OACN and DARK/NBI), B. Schneider (MIT), T. Laskar (Utah), B. P. Gompertz (U. Birmingham), D. B. Malesani (Radboud and DAWN/NBI), G. Finneran (UCD), J.F. Agui Fernandez (IAA-CSIC), C.C. Thoene (ASU-CAS), V. D'Elia (ASI-SSDC and INAF-OAR), N.R. Tanvir (U. Leicester), P. Jakobsson (U. Iceland) and G. Pugliese (API, Amsterdam) report on behalf of a larger collaboration:
We obtained spectroscopic observations of the orphan GRB afterglow candidate ZTF23aaoohpy/AT2023lcr (Andreoni et al., GCN 3402; Swain et al., GCN 34022; Kumar et al., GCN 34025; Adami et al., GCN 34030; Perley et al., GCN 34031; Jiang et al., GCN 34040; Chen et al., GCN 34043) with the James Webb Space Telescope on 12 August 2023 (DDT program 4554, PI Martin-Carrillo). This was about 55 days (27 days rest frame) after the likely explosion epoch of the event (Gompertz et al., GCN 34023). Observations were obtained with the NIRSpec clear prism in the 0.5-5.3 micron wavelength range.
Assuming a redshift of z=1.027 (Perley et al. GCN 34041), the obtained spectrum shows an excellent match to the spectrum of GRB-SN 1998bw (at 22 days) and 2017iuk (at 26 days), confirming the presence of a supernova component initially hinted by photometric observations (Martin-Carrillo et al., GCN 34370). Based on the observed spectral properties, we identify the supernova associated to ZTF23aaoohpy/AT2023lcr as a broad-lined type Ic SN similar to other SNe accompanying GRBs. To date, this is the furthest GRB-SN association with robust spectroscopic confirmation.
Further analysis and observations are ongoing.
We thank the staff of STScI for their work to get these observations rapidly scheduled, in particular Alison Vick, Tony Keyes, Mario Gennaro and Armin Rest.