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"2900 results found.
- Trigger 888312: Swift detection of 4U 1901+03
- GRB 190204A: Swift detection of a burst with a possible optical counterpart
- GRB 190202A: SAO RAS optical observations
- GRB 190129A: MAXI/GSC detection
- Swift Trigger 886157: MASTER optical observation
- IPN Triangulation of GRB 190117A (long)
- GRB 190114C: UKIRT JHK observation (CORRECTIONS)
- GRB 190114C: Continued UKIRT JHK observation
- GRB 190114C: UKIRT JHK observation
- GRB 190114C: REM optical/NIR detection
- GRB 190114B: Liverpool Telescope near-IR observations
- CORRECTED TARGET NAME: GRB 190114C: Planned XMM-Newton observation
- GRB 190114C: MASTER afterglow Detection
- IceCube-190104A: Swift-XRT observations
- GRB 190106A: GMG photometry in the 2nd night
- GRB 190106A: Swift detection of a burst with an optical counterpart
- GRB 181228A: Global MASTER Net OT detection
- GRB 181225A: KAIT Follow-Up Observations with Upper Limit
- Trigger 878548: Swift detection of AX 1631.9-4752
- Konus-Wind observation of GRB 181212A
- IPN Triangulation of GRB 181212A (long)
- MASTER: OTs detection during Fermi alert trigger 565936249 early observations
- GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)
- GRB 181203A: Swift detection of a burst
- Konus-Wind observation of GRB 181121A
- GRB 181125A: Swift detection of a burst
- GRB 181030A: MASTER Net OT detection
- GRB 181030A: SAO RAS optical observations
- IPN Triangulation of GRB 181028A (long)
- GRB 180728B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 554505003)
- GRB 181022A: Swift-XRT refined Analysis
- GRB 181020A: Swift/UVOT Detection
- GRB 181020A: Global MASTER Net OT observations
- GRB 181020A: VLT/X-shooter spectroscopy and redshift
- GRB 181020A: Swift detection of a burst with an optical counterpart
- GRB 181011A: Global MASTER Net optical inspection
- GRB 181011A: MAXI/GSC detection
- GRB180913A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 558557292)
- GRB 181008B: Global MASTER Net optical inspection
- GRB 180930A: Swift-XRT refined Analysis
- GRB 180930A: Swift detection of a burst
- GRB 180914B: OAJ multi-color follow-up
- IPN Triangulation of GRB 180914A (long)
- GRB 180914B: MASTER OT automatic dtection
- GRB 180914B: KAIT Optical Afterglow Candidate
- GRB 180828A: RATIR Optical and NIR Observations
- GRB 180828A: Swift-BAT refined analysis
- GRB 180828A: Swift-XRT refined Analysis
- GRB 180828A / Swift J1754.9-2548: Enhanced Swift-XRT position
- GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
- GRB 180821A: BOOTES-3/YA optical observations
- GRB 180809A: Swift-XRT afterglow detection
- GRB 180701A/MAXI J2119-045: CALET Gamma-Ray Burst Monitor data search
- GRB 180720B: MASTER Global Net OT observations
- GRB 180715B: AstroSat CZTI detection
- FRB 180714: MASTER optical inspection of the Fast Rado Burst Transient
- GRB 180721A: Swift detection of a burst
- GRB 180720C: LT observations
- GRB 180718A: MASTER optical observation
- GRB180715B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 553369644)
- GRB 180718A short GRB detected by IPN and found in ground analysis of BAT data
- Swift Trigger 848621 is not an astrophysical event
- IceCube-171106A: MASTER optical observation
- GRB 180709A: Optical limits
- GRB 180703A: Swift/UVOT Upper Limits
- GRB 180701A: MAXI/GSC detection
- GRB 180626C: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 551697835)
- Konus-Wind observation of GRB 180626B
- IPN Triangulation of GRB 180626B (short)
- GRB 180624A: Swift-BAT refined analysis
- GRB 180624A: MITSuME Okayama optical upper limits
- Konus-Wind observation of GRB 180618A (a short GRB with extended emission)
- GRB 180614A: MASTER observation
- Konus-Wind observation of GRB 180611A
- GRB 180602A: MITSuME Okayama optical upper limits
- IPN Triangulation of GRB 180526A (long)
- GRB180523B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 548793993)
- GRB 180512A: NOT upper limits
- GRB 180512A: Swift detection of a burst
- Swift trigger 831888: misidentification of 4U 1416-62
- GRB 180425A: Swift detection of a burst
- GRB 180410A: Fermi GBM observation
- GRB 180411A: Swift-BAT refined analysis
- GRB 180411A: Swift-XRT refined Analysis
- GRB 180411A: Swift detection of a burst
- GRB 180404A: Swift detection of a burst with an optical afterglow
- GRB 180402A: Swift-XRT refined Analysis
- GRB 180402A: KAIT Optical Upper Limit
- GRB180314A: GROND detection of the afterglow
- IPN Triangulation of GRB 180223A (long)
- GRB 180113A: AstroSat CZTI detection
- GRB 180116A CALET Gamma-Ray Burst Monitor detection
- GRB 180113A CALET Gamma-Ray Burst Monitor detection
- Konus-Wind observation of GRB 180113B
- GRB 180116A: MAXI/GSC detection
- Konus-Wind observation of GRB 180113A
- GRB 180113A: Fermi GBM observation
- GRB 180113A: Swift detection of a burst
- GRB 180102A: MASTER-Net robotic report
- IPN Triangulation of GRB 171216B