GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
3382 results found.
- LIGO/Virgo S190426c: GRAWITA transients from Asiago Schmidt wide field observations
- LIGO/Virgo S190425z: DECam Observations of the UVOT Candidate Region
- LIGO/Virgo S190426c: Continued LOAO Observation
- LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
- Fermi Trigger 578170097 / GRB 190428783 / GRB190428A: BALROG localization
- LIGO/Virgo S190426c: Additional Candidates from the Zwicky Transient Facility
- LIGO/Virgo S190426c: Continued infrared wide-field search with Palomar Gattini-IR
- LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient
- LIGO/Virgo S190426c: OAJ-GRANDMA observation report
- LIGO/Virgo S190425z: No source found at UVOT source location at 6 hrs after LVC report
- LIGO/Virgo S190426c: DDOTI/OAN Optical Observations
- LIGO/Virgo S190425z: Lulin observations of the Swift/UVOT transient
- LIGO/Virgo S190426c: COATLI Optical Observations of Galaxies
- LIGO/Virgo S190426c: MMT Follow-Up Observations
- LIGO/Virgo S190426c: Lick/KAIT Follow-Up Observations
- GRB 190427A: COATLI Optical Observations
- LIGO/Virgo S190426c: CNEOST Optical Observations
- LIGO/Virgo S190425z: CNEOST Optical Observations
- LIGO/Virgo S190425z: BOOTES-5/JGT observations of galaxies
- LIGO/Virgo S190425z: Additional Pan-STARRS transients in the skymap
- LIGO/Virgo S190425z: GRANDMA follow-up observations with Les Makes-T60, AZT-8 and Abastumani-T70
- LIGO/Virgo S190426c: SAO optical observation
- LIGO/Virgo S190425z: Further MMT Follow-Up Observations
- LIGO/Virgo S190425z: COATLI Observations of Galaxies
- LIGO/Virgo S190426c: HAWC follow-up
- LIGO/Virgo S190425z: YAHPT Optical Observation
- LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
- LIGO/Virgo S190425z: KMTNet Observation
- LIGO/Virgo S190425z: Swope follow-up observations
- LIGO/Virgo S190425z: KPED Follow-Up Observations
- LIGO/Virgo S190425z: OVRO-LWA simultaneous low frequency radio observations of localization region
- LIGO/Virgo S190425z: J-GEM optical follow-up observations with Subaru/FOCAS
- LIGO/Virgo S190425z: Xinglong/Schmidt follow-up observations
- LIGO/Virgo S190408an: Gaia Photometric Alerts transient candidates
- LIGO/Virgo S190425z: Fermi GBM Observations
- LIGO/Virgo S190425z: Lick/KAIT Follow-Up Observations
- Fermi GRB190425.09 Global MASTER-Net observations report
- LIGO/Virgo S190421ar: TAROT-GRANDMA observation report.
- LIGO/Virgo S190421ar: Lick/KAIT Follow-Up Observations
- Fermi GRB190420.98 Global MASTER-Net observations report
- Fermi GRB190419.41 Global MASTER-Net observations report
- LIGO/Virgo S190412m: GOTO optical coverage - no notable counterparts
- LIGO/Virgo S190408an: MAXI/GSC Observations
- GRB 190404C: MITSuME Akeno and Okayama optical upper limits
- LIGO/Virgo S190408an: CALET Observations
- CORRECTED TARGET NAME: GRB 190408A: MAXI/GSC detection
- GRB 140408A: MAXI/GSC detection
- GRB 140404B: MAXI/GSC detection
- GRB 190331B: Swift observations of a ground-detected burst
- GRB 190326A: 2.2m CAHA telescope optical limit
- Swift Trigger 895479: Detection of GRO J2058+42
- Swift Trigger 895257: Detection of GRO J2058+42 in outburst
- GRB 190326A: Swift detection of a short burst
- SWIFT GRB190323.85 Global MASTER-Net observations report
- Swift Trigger 894268: Detection of GRO J2058+42 in outburst
- Fermi Trigger 574676902 / GRB 190319353: BALROG localization
- GRB190219A: MASTER Global Robotic Net optical observation
- GRB190211A: GROWTH-India detection of optical afterglow
- GRB 190211A: DOAO optical observation
- Trigger 888312: Swift detection of 4U 1901+03
- GRB 190204A: MAXI/GSC detection
- Swift Trigger 887541: Swift detection of Swift J1728.9-3613
- IPN Triangulation of GRB 190129B (long/extremely bright)
- Swift Trigger 886157: MASTER optical observation
- Trigger 885456: Swift detection of MAXI J1631-479
- GRB 190114C: RTT150 optical observations
- GRB 190114B: optical afterglow observations in Mondy and Abastumani observatories
- GRB 190114B: Mondy optical afterglow detection
- GRB 190114C: NOT optical counterpart and redshift
- Konus-Wind observation of GRB 190103A
- GRB 190109A: Swift-BAT refined analysis
- Trigger 882561: Swift detection of MAXI J1631-479
- GRB 181228A: Mondy and AbAO optical upper limits
- GRB 181228A: possible NOT optical detection
- GRB 181228A: Xinglong-2.16m optical upper limit
- FRB 181228: Global MASTER Net optical inspection
- GRB 181227A: Global MASTER Net oprtical inspection
- Swift Trigger 880127 is not a GRB
- GRB 181228A: TSHAO optical upper limit
- GRB 181228A: Fermi GBM observation
- GRB 181228A: Global MASTER Net OT detection
- GRB 181228A: REM NIR detection
- GRB 181126A: MeerKAT radio observation
- GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)
- Swift Trigger 874754 is likely not an astrophysical event
- GRB 181201A: Zeiss-1000/CrAO optical observations
- GRB 181201A: Swift-XRT afterglow detection
- Short-duration GRB 181121.4: MASTER-Tavrida possible OT detection near the PGC galaxy during large Fermi error box inspection
- GRB 181028A: CALET Gamma-Ray Burst Monitor detection
- GRB 181030A: Swift detection of a burst with a possible optical counterpart
- GRB 181028A: Fermi GBM observation
- GRB 181028A: Fermi-LAT detection
- GRB 181027A: Swift detection of a burst
- Swift Trigger 866757: is probably not a GRB
- GRB 181011A: MAXI/GSC detection
- GRB 181008A: Insight-HXMT/HE detection
- GRB 181002A: Swift detection of a burst
- GRB 180923A: MAXI/GSC detection
- GRB 180914B : continued TSHAO optical observations
- GRB 180914B: MASTER OT automatic dtection