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"20967 results found.
- LIGO/Virgo G268556: Swift/UVOT observations of ATLAS17aeu
- LIGO/Virgo G268556: CALET Observations
- LIGO/Virgo G268556: iPTF Optical Transient Candidates
- Discovery Channel Telescope Imaging of ATLAS17aeu (LVCG268556)
- LIGO/Virgo G268556: VLA follow-up of ATLAS17aeu
- LIGO/Virgo G268556/GW170104: Global MASTER Net second OT detection
- LIGO/Virgo G268556: Swift-XRT detection of ATLAS17aeu
- LIGO/Virgo G268556: SWASP optical imaging
- LIGO/Virgo G268556/GW170104: Asiago Observations
- LIGO/Virgo G268556: Pan-STARRS1 observations of the skymap
- LIGO/Virgo G268556/GW170104: Global MASTER Net observations and first OT detection
- LIGO/Virgo G268556: ATLAS imaging of the skymap
- LIGO/Virgo G268556: DESGW/DECam observations
- LIGO/Virgo G268556: AGILE MCAL and Super-AGILE Observations
- LIGO/Virgo G268556: Mini-MegaTORTORA follow-up observations
- LIGO/Virgo G211117 / GW151226: LOFAR follow-up
- LIGO/Virgo G268556: Swift-XRT sources
- LIGO/Virgo G268556: observation regions by Project Mini-GWAC of SVOM
- LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
- LIGO/Virgo G268556: Fermi GBM Observations
- GRB 170101A: POLAR observation
- Trigger 729410: Swift detection of V2293 Oph
- GRB161219B - Anticipated hyperluminal evidence
- GRB 161214B: MASTER-Kislovodsk early optical observations
- GMRT radio detection of GRB 161219B
- GRB 161214A: MASTER-IAC early optical observations
- GRB 161219B: Spectroscopic detection of the associated SN with OSIRIS/GTC
- GRB 161224A: TSHAO optical observations
- GRB 161224A: Swift/UVOT Upper limits
- Trigger 728094, Swift-BAT refined analysis
- GRB 161219B: UKIRT near-IR afterglow detection
- GRB 161219B: Rapid ALMA Observations & Detection
- GRB 161219B: SALT observations
- GRB 161219B: VLT/X-shooter redshift
- GRB 161214B: optical spectroscopy of the foreground SDSS object
- GRB 161202A: 15 GHz upper limits from AMI
- GRB 161129A: 15 GHz upper limits from AMI
- GRB 161220A: LCO-FTS observations
- GRB 161219B: VLA Detection
- GRB 161220A: GROND Upper Limits
- GRB 161219B: ISON/Terskol optical observations
- GRB 161220A: Swift/UVOT Upper Limits
- GRB 161219B: Swift/UVOT Detection
- GRB 161219B: Watcher optical observations
- GRB 161219B: LCO Sutherland observations
- GRB 161219B: GROND afterglow observations
- GRB 161218A: TAROT Calern observatory optical observations
- GRB 161217A: TAROT Calern observatory optical observations
- GRB 161218B: POLAR observation
- GRB 161218A: POLAR observation
- GRB 161217A: Swift/UVOT Upper Limits
- GRB 161214B: AbAO and ISON/Terskol optical observations
- GRB 161214B: Mondy optical observations
- Fermi-LAT Gamma-ray Observations of IceCube-161210
- GRB 161214B: Swift/UVOT Afterglow Confirmation
- IceCube-161210: Kanata/HONIR near-infrared follow-up observation
- GRB 161214B: RATIR Optical and Near-Infrared Observations
- GRB 161214B: TAROT Calern observatory optical observations
- GRB 161214B: Chante-perdrix observatory optical observations
- GRB 161214B: Swift/UVOT Observations
- GRB 161214B: NOT optical observations, possible counterpart
- GRB 161214A: NOT observations of the afterglow
- GRB 161214A: GROND afterglow observations
- GRB 161214A: TAROT Calern observatory optical observations
- INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161210
- GRB 161129A: GTC redshift of the likely host galaxy
- GRB 161129A: NOT optical observations and candidate host galaxy
- GRB 161129A: KWFC z-band photometry
- MASTER: Optical Blazar Flare Detection during Fermi trigger 502272781 inspection
- GRB 161202A: RATIR Optical and NIR Observations
- GRB 161202A: Swift/UVOT Upper Limits
- GRB 161129A: Mondy optical observations
- GRB 161129A: ISON/UAFO optical observations
- GRB 161129A: MITSuME Okayama Ks-band Observation
- GRB 160821B: HST detection of the optical and IR counterpart
- GRB 161129A: Swift/UVOT Detection
- GRB 161129A: Tautenburg Ic-band observations
- GRB 161129A: TSHAO optical observations / possible afterglow+host galaxy
- GRB 161123A: Swift-XRT observations
- GRB 161123A: Tiled Swift observations
- GRB 161117A: SMARTS optical/IR afterglow observations
- GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
- GRB 161108A: 15 GHz upper limits from AMI
- GRB 161117A: MASTER-OAFA (Argentina) prompt OT observations
- GRB 161117A: TAROT La Silla observatory optical observations
- GRB 161117A: GMG observation limit
- GRB 161117B: Swift/UVOT Upper Limits
- GRB 161117A: Swift/UVOT Detection
- GRB 161117B: LCO optical observations
- GRB161117A: REM optical and NIR afterglow detection
- GRB 161113A: Swift/UVOT Upper Limits
- GRB 161113A: RATIR Optical and NIR Observations
- GRB 161109A: Swift/UVOT Upper Limits
- GRB 161104A: Magellan imaging and spectroscopy
- GRB 161108A: continued TSHAO optical observations
- GRB 161104A: Chandra X-ray observations
- GRB 161109A: Swift-XRT observations
- GRB 161108A: TSHAO optical observations
- GRB 161108A: Swift/UVOT Upper Limits
- GRB 161109A: Tiled Swift observations