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"101 results found.
- GRB 251013C: AstroSat CZTI detection
- Konus-Wind detection of GRB 250119B
- GRB 250108B: Swift detection of a burst
- Fermi GRB 241104A: Global MASTER-Net observations report
- GRB 241025A: Swift/UVOT Detection
- GRB 240912A: Swift/UVOT Detection
- Fermi trigger No 744459130: Global MASTER-Net observations report
- GRB 240727C: AstroSat CZTI detection of a long burst
- LAT GRB240513.31: Global MASTER-Net observations report
- Fermi trigger No 729703985: Global MASTER-Net observations report
- Swift GRB231214.85: Global MASTER-Net observations report
- GRB 231020B: AstroSat CZTI detection
- GRB 230728A: Swift/UVOT Upper Limits
- LIGO/Virgo S230608as: Global MASTER-Net observations report
- GRB 230405B: Swift/UVOT Upper Limits
- GRB 230204A: Swift/UVOT Upper Limits
- Swift GRB221226.95: Global MASTER-Net observations report
- GRB 220803A: AstroSat CZTI detection
- GRB 220715B: Swift/UVOT Upper Limits
- Fermi GRB 211219B: Global MASTER-Net observations report
- Swift GRB210807.78: Global MASTER-Net observations report
- Fermi GRB 210606A: Global MASTER-Net observations report
- GRB 210517A: Swift/UVOT Upper Limits
- GRB 200922A: chance superposition between optical afterglow and archival star
- GRB 200906A: Swift/UVOT Upper Limits
- Improved IPN error box for GRB 200415A (consistent with the Sculptor Galaxy)
- Swift GRB200306.01: Global MASTER-Net observations report
- GRB 200216B: Swift/UVOT Upper Limits
- Swift GRB191227.07: Global MASTER-Net observations report
- GRB 191024A: Swift/UVOT Upper Limits
- LIGO/Virgo S190425z: Swift UVOT - no new sources identified, and a summary of the Swift UVOT processing of GW triggers.
- LIGO/Virgo S190426c: Swift rapid follow-up observations of S190425z and S190426c and URL for observation log for all future events
- Swift GRB190427.19 Global MASTER-Net observations report
- LIGO/Virgo S190421ar Global MASTER-Net observations report
- GRB 181022A: Swift/UVOT Upper Limits
- GRB 180824A: MASTER inspection IPN short GRB error box
- GRB 180620A: Swift-XRT refined Analysis
- GRB 180331A: Swift/UVOT Upper Limits
- GRB 180329B: Swift/UVOT Detection
- Trigger 813449: Swift detection of large burst from XTE J1701-407
- GRB 171216A: Swift/UVOT Upper Limits
- GRB 171027A: Swift-XRT refined Analysis
- Konus-Wind observation of GRB 170906A
- GRB 170419A: Swift/UVOT Upper Limits
- GRB 161113A: Swift/UVOT Upper Limits
- GRB 161105A: Swift/UVOT Upper Limits
- GRB 161001A, Swift-BAT refined analysis (likely a short GRB)
- GRB 160815A: Swift/UVOT Detection
- Swift-BAT trigger 686845 was due to noise near a known source
- GRB 160325A: Further Swift/UVOT Observations
- GRB 151228B: Swift/UVOT Detection
- GRB 150819A: Swift/UVOT Upper Limits
- Swift trigger 637807 is probably not an astrophysical source
- GRB 150323C, Swift-BAT refined analysis
- GRB 150222A: Swift/UVOT Upper Limits
- Konus-Wind observation of GRB 141202A
- GRB 131002B: Swift/UVOT Upper Limits
- GRB 130925A: Swift/UVOT Upper Limits
- GRB 130907A: MASTER refined analysis
- GRB 130831B: Swift/UVOT Upper Limits
- GRB 130715A: Suzaku WAM observation of the prompt emission
- Trigger 538084: Swift detection of XTE J1739-302
- GRB 120624B Suzaku WAM observation of the prompt emission
- GRB 120324A: Swift/UVOT Upper Limits
- Swift J1822.3-1606: Transient Magnetar or Be X-ray Binary?
- IBAS Alert n. 6057 is not due to a GRB
- Trigger 424161: Swift/BAT trigger on XTE J1946+274/GRO J1944+26
- GRB 100606A: Swift/UVOT Upper Limits
- IBAS Alert 5992 is not a GRB, but XTE J1855-026
- GRB 100213A: Swift XRT refined analysis
- Swift/BAT Detects an Outburst from XTE J1901+014
- Swift Trigger #382159 is due to XTE J1752-223
- Swift-BAT trigger 373691 is a galactic bulge transient
- GRB 091010: RXTE detection
- GRB 090516: Swift/UVOT Observations
- GRB 081109A: Possible Swift-UVOT detection
- GRB 081109: Swift/UVOT upper limits
- GRB 080905B: Refined UVOT Analysis
- Swift detection of XTE J1701-407
- Trigger 317205: Swift detection of an outburst from XTE J1701-407
- GRB 080603B: Swift-XRT refined analysis
- A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
- Swift/UVOT observations of GRB070805
- GRB 070714A: Swift/UVOT Upper limits
- GRB 070309: Swift/UVOT Upper Limits
- GRB 061028: Swift/UVOT Observations
- H11603: An X-ray flare from V4641 Sgr, or a possible XRF
- SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
- IPN detection of continued activity from SGR1806-20
- Detection of activity from SGR 1900+14 with the RXTE/PCA
- RXTE Observations of SGR 1900+14
- The X-ray Flash 011030 ('GRB 011030')
- SGR 1900+14 : RXTE observations
- Further Optical Observations of GRB 010324
- Optical Observations of GRB 010324
- IPN TRIANGULATION OF GRB010115
- GCN resumes full operations
- Chandra observation of the X-ray afterglow of GRB991216
- GRB 990506: Limits on the possible optical transient
- GRB990308 (Trig. 7457), optical observations