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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"26363 results found.
- GRB 070129: afterglow confirmation
- GRB070126: Swift-XRT Observation
- GRB 070129: Swift/UVOT Upper limits
- GRB 070125: optical observation
- GRB 070129, Swift-BAT refined analysis of a particularly long
- GRB 070129: Xinglong TNT optical Upper Limit
- GRB 070129: Swift-XRT Refined Analysis
- GRB 070129: VLT observations
- GRB 070125: An IR Point Source and an Apparent Host Galaxy
- GRB 070129: Swift detection of a burst
- GRB 070126: Swift/UVOT refined analysis
- GRB 070125: MITSuME Okayama optical observation
- GRB 070125: optical observations
- GRB 070126: VLT observations
- GRB 070124: Suzaku WAM observation of the prompt emissions
- GRB 070125: UVOT Detection in Ultraviolet Filters
- GRB 070126, Swift-BAT refined analysis of a very faint burst
- GRB070125: Optical observation by Kanata
- GRB070124: Swift-XRT Observation
- Possible GRB 070126: Swift/UVOT Upper Limit
- GRB 070125: UVOT Observations of a Fading Optical Afterglow
- GRB 070125: Xinglong TNT optical observations
- GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
- GRB 070125: Lick 3m Spectroscopy
- GRB070125: Swift-XRT Refined Analysis
- GRB 070125: SARA detection in R
- GRB 070125: P60 Optical Afterglow Candidate
- GRB 070126?: Swift detection of a possible burst
- GRB070125 redshift request
- IPN localization of GRB070124 (short duration, hard spectrum)
- GRB 070110: Ep,i - Eiso correlation
- GRB 070107: Suzaku WAM observation of the prompt emission
- GRB070110: Swift XRT Team refined analysis
- GRB 070110, Swift-BAT refined analysis
- GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
- GRB 070110: Swift detection of a burst with a possible optical afterglow
- GRB 070107: Possible UVOT Afterglow
- GRB 070107, Swift-BAT refined analysis
- GRB 070107: Swift detection of a burst
- VLA observation of GRB 061222B
- VLA detection of GRB 061222A
- GRB070103: APO SPIcam i' and z' limits
- GRB070103: KPNO 4m+FLAMINGOS J limit
- GRB 070103: Swift/UVOT Upper limits
- GRB070103: Swift XRT refined analysis
- GRB 070103, Swift-BAT refined analysis
- GRB 070103: NOT observations
- GRB 070103: TAROT Calern observatory optical observations
- Retractions of previous Swift-BAT triggers
- erratum : SDSS Pre-burst Observations of GRB061126
- GRB 061210: Swift/XRT Astrometry Correction
- GRB 050826: MDM Redshift
- GRB 061222A: Confirmation of Gemini Afterglow Candidate
- GRB 061222A: Xinglong Optical Limit
- GRB 061222A: Gemini Afterglow Candidate
- GRB 061222B, Swift-BAT refined analysis
- GRB061222A Swift/UVOT: Upper Limits
- GRB 061222B: Swift/UVOT Upper limits
- GRB 061222B: Observation with the KANATA 1.5m telescope
- GRB 061222A: Observation with the KANATA 1.5m telescope
- GRB 061222B: BOOTES-IR optical observations
- GRB 061222B: SARA upper limit
- GRB 061217: Magellan host galaxy redshift
- GRB 061222A, Swift-BAT refined analysis
- GRB 061222B: REM NIR/optical observations
- GRB 061222B: TAROT La Silla observatory optical observations
- GRB 061222B: Swift detection of a burst
- GRB 061222b: optical afterglow
- GRB 061222A: Prompt ROTSE-III Optical Limits
- GRB 061222: Swift detection of a burst
- GRB 061218: TAROT La Silla observatory optical observations
- GRB 061217: TAROT Calern observatory optical observations
- GRB 061218: TORTOREM optical upper limits
- GRB 061218, Swift-BAT refined analysis
- GRB061217: VLT NIR observations
- GRB 061218, SMARTS optical/IR observations
- GRB 061218: REM prompt observations
- Swift triggers (#251863) on a possible burst
- GRB061217: Swift/UVOT refined analysis.
- GRB 061217: optical observations at Calar Alto
- GRB061217 - Swift/XRT refined analysis
- GRB 061217, Swift-BAT refined analysis
- GRB 061217: Magellan Observations
- GRB 061217: REM prompt observations
- GRB 061217: ROTSE-III Optical Limits
- GRB061210: Swift/UVOT observations
- GRB 061210: Swift XRT analysis - Possible counterparts
- GRB 061210: Gemini/GMOS Observations
- GRB 061126: Radio Observations
- GRB061210: Radio Observations
- GRB 061202: Suzaku WAM observation of the prompt emission
- GRB 061210, Swift-BAT refined analysis of the SHB
- Optical Afterglow observations of GRB 061126
- GRB 060926: MASTER: discovery of the optical flare
- GRB 061201: UVOT Observations of a Fading Optical Afterglow
- GRB 061202: TORTOREM optical upper limits
- GRB 061201: VLT optical decay
- GRB 061201: SOAR Confirmation of Candidate Afterglow
- GRB061202: FRAM early follow-up limit
- GRB061202 optical limit by "Pi of the Sky"