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"
129 results found.
- GRB 250507A: SVOM detection of a long burst
- GRB 250211A: SVOM trigger sb25021103 is not a GRB
- LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
- GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
- Fermi GRB 241209E: Global MASTER-Net observations report
- GRB 240727A: Swift-XRT refined Analysis
- GRB 240513A: Fermi GBM observation
- Swift Trigger 1220736: detection of 4U 1543-62.
- Fermi GRB 240112D: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
- Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
- LIGO/Virgo/KAGRA S230704f: Updated Sky localization
- LIGO/Virgo S230615i: Global MASTER-Net observations report
- GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
- GRB 230321B: AstroSat CZTI detection
- GRB 230320B: AstroSat CZTI detection
- Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
- GRB 220806A: Swift detection of a burst
- Konus-Wind detection of GRB 220203A
- GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
- GRB 211221A: Swift detection of a burst
- Fermi GRB 211211B: Global MASTER-Net observations report
- IceCube Alert 211125.27: Global MASTER-Net observations report
- Trigger 1062273: Swift detection of 4U 1700-377
- GRB 210708A: Swift/UVOT Upper Limits
- GRB 210610B: Swift/UVOT Detection
- Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
- Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
- Swift trigger 1047857 is 4U 1700-377
- GRB 210424B: AstroSat CZTI detection
- GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
- GRB 200529A: Swift detection of a burst
- GRB 200514B: Fermi GBM observation
- Fermi trigger No 611434353: Global MASTER-Net observations report
- GRB 200107B: Swift detection of a burst
- Konus-Wind observation of GRB 191221B
- Swift GRB 191221B: Global MASTER-Net observations report
- Fermi trigger No 596690552: Global MASTER-Net observations report
- Fermi trigger No 596387570: Global MASTER-Net observations report
- LIGO/Virgo S190901ap: Second Epoch Hobby-Eberly Telescope observations of ZTF19abvionh
- LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
- Fermi trigger No 587775150 Global MASTER-Net observations report
- GRB 190718A: Swift detection of a burst
- LIGO/Virgo S190426c: Updated localization from LIGO and Virgo data
- Problem with GCN Circular and status of the fix
- GRB 190311A: Swift detection of a burst with optical counterpart
- GRB 190220A: Swift detection of a burst with an optical counterpart
- Trigger 888312: Swift detection of 4U 1901+03
- GRB 190109B: Swift detection of a burst
- Swift trigger 831888: misidentification of 4U 1416-62
- LIGO/Virgo G297595: NIR Observations following GW170814
- LIGO/VIRGO G298048: AAT/AAO spectroscopic observations of the GW counterpart candidate SSS17a/DLT17ck
- LIGO/Virgo G296853: Fermi-LAT search for high-energy gamma-ray counterpart
- Fermi GBM Detection of possible burst from AXP 4U 0142+61
- GRB 170604A: Swift/UVOT Observations
- GRB 170419A: Swift detection of a burst
- LIGO/Virgo G277583: Asiago spectroscopic classification of ATLAS17byo and ATLAS17cgg
- LIGO/Virgo G275697: optical spectroscopy of Swift/XRT source 1
- GRB 170208B: Swift/UVOT Upper Limits
- GRB 170101B: Astrosat CZTI detection
- Swift Trigger 718766 is not an astrophysical event.
- Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
- LIGO/Virgo G197392 / LVT151012: Identification of a GW CBC Candidate
- GRB 160409A found in Swift BAT ground analysis
- GRB 160412A: Swift-XRT refined Analysis
- GRB 160314A: Swift detection of a burst
- GRB 160121A: Swift detection of a burst
- Swift detection of 4U 1850-03
- GRB 150428A: Swift detection of a burst
- GRB 150317A: Swift detection of a burst
- GRB 150301A: Fermi GBM observation
- Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)
- Fermi GBM Observations of Magnetar 4U 0142+61
- Trigger 632888: Swift detection of the magnetar 4U 0142+61
- Trigger 631747: Swift detection of 4U 0614+09
- Swift detection of 4U 1700+24 (= V* V934 Her)
- Swift detection of 4U 1700+24 (= V934 Her)
- GRB 141020A: Swift detection of a burst with an optical counterpart
- Swift detection of outburst from 4U 1700+24
- Swift trigger 609139 is probably 4U 1850-03
- GRB 140706A: Swift detection of a burst with an optical counterpart
- GRB 140305A: Swift detection of a burst
- Observation of possible GRB/TDE 130925A by INTEGRAL/SPI-ACS: three activity episodes
- Swift Trigger 558828 is not an interesting event
- Swift Trigger 557674 was due to an onboard position error
- GRB130427A: Swift/UVOT followup observations of an Optical Afterglow
- GRB 120817A: Swift detection of a burst
- Swift Trigger 530581: GRB 120811A or a galactic transient
- Swift detection of 4U 1630-47
- GRB 120118B: Swift detection of a burst
- AXP 4U 1042+61: Mondy optical observations
- AXP 4U 0142+61: Swift-BAT refined analysis (trigger 511611)
- Swift detection of an SGR burst from AXP 4U 0142+61
- AXP 4U 0142+61: Fermi GBM detection
- AXP 4U 0142+61: Swift-BAT refined analysis
- Swift detection of a SGR-like burst from the AXP 4U 0142+61
- GRB 110205A: Swift-BAT refined analysis
- Swift/UVOT observations of GRB110201A
- GRB 110112A: Swift detection of a possible short burst
- GRB 101213A: Swift detection of a burst