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"106 results found.
- GRB 260616B/EP260616a: SVOM/GRM detection of a burst
- EP260430a: Global MASTER-Net observations report
- GRB 260206A: probable hard X-ray burst from 4U 0513-40
- GRB 260206A: Swift-XRT observations
- GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
- GRB 251116D: AstroSat CZTI detection
- SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
- sb25081602: Swift-XRT observations
- SVOM/sb25081602: detection of a likely X-ray transient
- The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
- Fermi GRB 250621A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 250322A (short)
- GRB 250211A: SVOM trigger sb25021103 is not a GRB
- LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
- Fermi trigger No 745871958: Global MASTER-Net observations report
- GRB 240812B: AstroSat CZTI detection of a long burst
- GRB 240713B: AstroSat CZTI detection of a long burst
- Swift Trigger 1220736: detection of 4U 1543-62.
- LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
- Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
- GRB 221027A: AGILE detection
- GRB 220813A: Swift/UVOT Detection
- GRB 220107A: AstroSat CZTI detection
- Trigger 1062273: Swift detection of 4U 1700-377
- GRB 210702A: AGILE 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
- GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
- Konus-Wind observation of GRB 201218A
- Fermi GRB 201007A: Global MASTER-Net observations report
- GRB 200906A: Swift/UVOT Upper Limits
- LIGO/Virgo S200316bj: Global MASTER-Net observations report
- LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
- GRB 200131A: Swift-BAT refined analysis
- LIGO/Virgo S191124be: Global MASTER-Net observations report
- LIGO/Virgo S190829u Global MASTER-Net observations report
- Fermi trigger No 584583925 Global MASTER-Net observations report
- Trigger 888312: Swift detection of 4U 1901+03
- Swift trigger 831888: misidentification of 4U 1416-62
- GRB 180305A: Fermi-LAT detection
- Fermi GBM Detection of possible burst from AXP 4U 0142+61
- GRB 170531B: Swift/UVOT Detection
- Swift Trigger 718766 is not an astrophysical event.
- GRB 161014A: Swift/UVOT Detection
- Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
- GRB 160409A found in Swift BAT ground analysis
- GRB 160203A: Swift/UVOT Detection
- Swift detection of 4U 1850-03
- GRB 150801B: Enhanced Swift-XRT position
- Swift 650221/IGR J00291+5934: Liverpool Telescope observations
- 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)
- Swift detection of outburst from 4U 1700+24
- Swift trigger 609139 is probably 4U 1850-03
- Swift Trigger 558828 is not an interesting event
- Swift Trigger 557674 was due to an onboard position error
- Swift Trigger 530581: GRB 120811A or a galactic transient
- Swift detection of 4U 1630-47
- 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 101225A: Swift/UVOT Detection
- GRB 101020A: MASTER prompt and afterglow limit
- GRB 100324B: Suzaku WAM observation of the prompt emission
- Swift Trigger 381591: Uncatalogued UVOT Source
- GRB 090728: Swift/UVOT Upper Limits
- GRB 071021, Swift-BAT refined analysis
- Swift trigger on 4U 1700-377 while star tracker loss-of-lock
- Retractions of previous Swift-BAT triggers
- Swift detection of an outburst from the 4U 1246-58 LMXB burster
- GRB060428A: Swift/UVOT observations.
- GRB 060218: rebrightening
- GRB 060111A: refined UVOT anaysis
- IBAS GRB Alerts 1978-1980
- GRB040903 - A XRF?
- GRB021004, late time optical observations
- GRB021004, late-time optical observations
- GRB 021004: optical observations
- GRB 991216, HST/STIS observations
- GRB 991216 RXTE ASM Observations
- IPN error box for GRB991216
- Chandra observation of the X-ray afterglow of GRB991216
- GRB 991216 Optical Observations
- VLT spectra of GRB991216
- GRB991216 Optical and IR observations
- IR observations of GRB991216
- GRB991216 radio observations
- GRB991216 radio observations
- GRB991216, optical observations
- Refined IPN localization of GRB991216