April 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 34169] LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36326 SUBJECT: LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a DATE: 24/04/26 21:27:56 GMT FROM: Damien Dornic <ddornic(a)km3net.de> E. G. Elhooseiny (NRIAG), D. Dornic (CPPM), M. Pillas, S. Antier (OCA), J. Dibasso (Berkeley) A. Klotz (IRAP), P. Thierry (AGORA association), S. Karpov (FZU), C. Andrade (UMN), M. Coughlin (UMN), P.A. Duverne (APC), P. Hello (IJCLAB), I. Tosta e Melo (UniCT-DFA), T. Pradier (Unistra/IPHC), D. … [View More]Turpin (CEA), M. Freeberg (KNC), H-B Eggenstein (KNC), J.-G. Ducoin (CPPM) Report on behalf of GRANDMA collaboration. We responded to the detection of a candidate counterpart EP240426a by EP/FXT (H. Sun et al, GCN 36313). We investigated in ATLAS forced photometry any possible previous detection from 2024-04-26T00:41:14 to 2024-04-23T01:27:14. No detection at mag [12.2 - 20.0] mag in the orange filter. We then performed observations with GRANDMA (Kilonova-catcher telescopes in Australia and LesMakes-T60 at la Reunion) of EP240426a from 2024-04-26T11:18:00 to 2024-04-26T18:03:15 UTC, under moderate weather conditions. We used T0 as the LIGO/Virgo/Kagra S240422ed GW candidate event (LIGO-Virgo-Kagra, GCN 36236). In the following table we report the preliminary photometry of our observations. Upper limits are reported at the 5-sigma limit, in the AB system. T-T0 (day)| MJD | Observatory | Exp. | Filter | Upp.Mag. | Comments ------------------------------------------------------------------------------------------------------------ 3.58 |60426.477894 | KNC |10x180s| Johnson V | 16.7 | calibrated in R, Gaia 3.63 |60426.528530 | KNC |7x180s | Rc | 16.6 | calibrated in sdssg, PS1, low elevation and moon 3.76 |60426.652754 | LesMakes-T60|5x120s | Clear | 19.5 | calibrated in sdssr, PS1 3.78 |60426.668757 | LesMakes-T60|15x120s| Clear | 20.9 | calibrated in sdssr, PS1 3.80 |60426.696710 | LesMakes-T60|40x120s| sdssr | 21.2 | calibrated in sdssr, PS1 All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022). In our low latency analysis (Antier & Karpov, in prep), comparing to PS1, we did not find any new candidates in our frames from LesMakes-T60 within 15 arcmin radius centered around ra=121.8567 dec=-29.4609 Our results are consistent with the non-detection reported by GMG (GCN 36315), DECam-r (GCN 36317) and YAHPT (GCN 36323). We can provide any image from this campaign by request. We thank the EP collaboration for useful communication. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics [2]. Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (kilonovacatcher.in2p3.fr). View this GCN Circular online at https://gcn.nasa.gov/circulars/36326. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 34168] LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36325 SUBJECT: LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a DATE: 24/04/26 21:26:32 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> A. J. Levan (Radboud), N. R. Tanvir (U. Leicester), D.T.H. Steeghs (Warwick) report for the ENGRAVE collaboration: The field of EP240426a (Sun et al., GCN 31313), the X-ray transient suggested as a possible counterpart to S240422ed (LVK, GCN 36236), has been observed multiple … [View More]

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[vsnet-grb-info 34167] GRB 240426A: AstroSat CZTI detection
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36324 SUBJECT: GRB 240426A: AstroSat CZTI detection DATE: 24/04/26 17:17:25 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> G. Waratkar (IITB), J. Joshi (IUCAA), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, … [View More]

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[vsnet-grb-info 34166] EP240426a: YAHPT optical upper limit
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36323 SUBJECT: EP240426a: YAHPT optical upper limit DATE: 24/04/26 16:57:35 GMT FROM: Tianrui Sun at Purple Mountain Obs,CAS <trsun(a)pmo.ac.cn> Tian-Rui Sun, Jin-Jun Geng, Jian Chen, Yan-Long Hua and Lei Hu report on behalf of the YAHPT team: Following the detection of EP240426a by Einstein Probe (Sun et al., GCN 36313), we use the Yaoan High Precision Telescope at Yaoan Astronomy Observation Station (Yunnan province, China) to search and follow up.… [View More]

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[vsnet-grb-info 34165] XMM-Newton observation of EP240426a
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36322 SUBJECT: XMM-Newton observation of EP240426a DATE: 24/04/26 16:45:04 GMT FROM: Norbert Schartel at XMM-Newton/ESA <xmmtoo(a)sciops.esa.int> XMM-Newton has scheduled an observation of the field of EP240426a, the potential X-ray counterpart of S240422ed (The LIGO-Virgo-KAGRA Collaboration, GCN 36236) reported in GCN 36313, at location RA=08h07m25.61s, Dec=-29d27'39.2'', starting at 20:10 UT, on April 26 2024, for an exposure time of 45 ks. … [View More]

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[vsnet-grb-info 34164] LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36321 SUBJECT: LIGO/Virgo/KAGRA S240426dl: Identification of a GW compact binary merger candidate DATE: 24/04/26 16:29:40 GMT FROM: emiliarose.chick(a)ligo.org We identified the compact binary merger candidate S240426dl during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-04-26 15:18:03.773 UTC (GPS time: 1398179901.773). The candidate was found by the CWB [1], GstLAL [2], and MBTA [3] analysis … [View More]pipelines. S240426dl is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.2e-08 Hz, or about one in 7 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240426dl The classification of the GW signal, in order of descending probability, is Terrestrial (70%), BBH (30%), BNS (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Three sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 25 seconds after the candidate event time. * cwb.multiorder.fits,0, an initial localization generated by cWB [1], distributed via GCN notice about 2 minutes after the candidate event time. * cwb.multiorder.fits,1, an initial localization generated by cWB [1], distributed via GCN notice about 7 minutes after the candidate event time. The preferred sky map at this time is cwb.multiorder.fits,1. For the cwb.multiorder.fits,1 sky map, the 90% credible region is 2024 deg2. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/36321. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 34163] LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36320 SUBJECT: LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a DATE: 24/04/26 16:03:13 GMT FROM: Dingrong Xiong at Yunnan Observatories of CAS, China <xiongdingrong(a)ynao.ac.cn> D. R. Xiong, J. M. Bai, J. R. Mao, Y. F. Fan, C. J. Wang, Y. X. Xin, X. H. Zhao (Yunnan Observatories of CAS), E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, … [View More]

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[vsnet-grb-info 34162] LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36319 SUBJECT: LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam DATE: 24/04/26 16:02:40 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> C.K. Li (IHEP, CAS), D. Y. Li, H. Q. Cheng, J. W. Hu, H. Sun, C. C. Jin (NAOC, CAS), J. Guan, H. S. Zhao, Y. Chen, S.M. Jia, W. W. Cui, J. Zhang, H. Feng, W. Li, C. Z. Liu, F. J. Lu, L. M. Song, J. Wang, J. J. Xu, D. W. Han, S. N. Zhang, X.… [View More] F. Zhao (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), P. Friedrich, V. Burwitz, N. Meidinger, K. Nandra, A. Rau (MPE), B. Cordier (CEA), B. Zhang (UNLV), W. D. Zhang, Z. X. Ling, Y. Liu, H. Y. Liu, Y. F. Xu, W. Yuan, M. Zhang, C. Zhang (NAOC, CAS) on behalf of the Einstein Probe team We report the results from a follow-up observation with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission, on one of the potential optical counterparts, namely AT 2024hfq, as reported by DECam (Cabrera et al. GCN #36298). Our EP-FXT observation started at 2024-04-25 11:57:54 (UTC) with an exposure time of 1189 seconds. An X-ray source was signifcantly detected at the position of R.A. = 126.2886, DEC. = -24.7273 (R.A. = 08:25:09.26, DEC. = -24:43:38.3), with a position uncertainty of 10" (90% C.L. statistical and systematic). This position is 9.4 arcsec away from AT 2024hfq, and 9.7 arcsec away from the nearby galaxy WISEA J082508.82-244345.9. The absorption-corrected flux in 0.5-10 keV is about 2.7 x 10 ^-13 erg/s/cm2 assuming a power-law spectrum with a photon index of 2.0 with Galactic absorption. No previously known X-ray sources are found within the error circle around this position. A flux upper limit set by the eRASS1 survey is 2.4 x 10^-13 erg/s/cm2 (99.9% C.L.) in 0.2-5.0 keV . Please note that EP-FXT is currently undergoing in-flight calibration, and the derived source parameters may be subject to larger uncertainties than quoted here; so please use them with caution. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/36319. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 34161] GRB 240414A: NOEMA detection
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36318 SUBJECT: GRB 240414A: NOEMA detection DATE: 24/04/26 15:39:53 GMT FROM: Antonio de Ugarte Postigo at OCA <deugarte(a)oca.eu> A. de Ugarte Postigo (CNRS/OCA & LAM), M. Bremer (IRAM), C. C. Thoene (ASU-CAS), J. F. Agui Fernandez (CAHA), S. Antier (OCA), S. Basa (LAM), M. Michalowski (AOI-AMU), D. A. Perley (LJMU), J.-G. Ducoin (CPPM) report: We observed the field of GRB 240414A (Caputo et al. GCN 36083; Myers et al. GCN 36120; Cheung et al. … [View More]

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[vsnet-grb-info 34160] LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
by GCN Circulars 26 Apr '24

26 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36317 SUBJECT: LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection DATE: 24/04/26 15:31:29 GMT FROM: Antonella Palmese at Carnegie Mellon University <apalmese(a)andrew.cmu.edu> Lei Hu (CMU), Brendan O'Connor (CMU), Antonella Palmese (CMU), Tomás Cabrera (CMU), Igor Andreoni (UMD), Keerthi Kunnumkai (CMU), report on behalf of the GW-MMADS team: During GW-MMADS DECam follow-up (Palmese et al., GCN 36245) of the LIGO/Virgo/KAGRA event … [View More]

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