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"892 results found.
- Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
- IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Fermi-LAT Gamma-ray Observations of IceCube-190922B
- LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S190923y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IceCube-190922A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- HAWC-190916A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190910d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190901ap: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
- LIGO/Virgo S190828l: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190828j: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
- IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
- IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
- Fermi-LAT Gamma-ray Observations of IceCube-190712A
- Fermi-LAT Gamma-ray Observations of IceCube-190504A
- LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
- GRB 190326A: Swift XRT and UVOT follow-up observations
- GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
- INTEGRAL observations of the events in the GWTC-1 catalog
- GRB 181201A: a long GRB detected by INTEGRAL
- GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
- GRB 180809A: further Swift/XRT observations
- GRB 180701A/MAXI J2119-045: CALET Gamma-Ray Burst Monitor data search
- GRB 180728A: VLT/X-shooter redshift of a nearby energetic GRB
- Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs
- GRB 180701A: MAXI/GSC detection
- Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
- Swift trigger 781740: Further analysis from Swift and Fermi/GBM
- Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
- Trigger 780207: Swift triggers again on AXP CXOU J164710.2-455216/PSR J1647-4552
- LIGO/Virgo G298048: Chandra X-ray Update on GW170817
- LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
- LIGO/Virgo G298936: Astrosat CZTI upper limits
- LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
- LIGO/Virgo G298048: Chandra X-ray observations
- GRB170730A detecetd by INTEGRAL. Refined analysis
- Fermi GBM Detection of possible burst from AXP 4U 0142+61
- GRB 170524A: Swift detection of a burst (or possible new SGR)
- LIGO/Virgo G275697: DLT40 follow-up observation
- LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
- GRB 160821B: Swift-BAT refined analysis
- GBM observation of SGR-like burst from the direction of PSR 1119-6127
- Trigger 706396: Swift detection of a short burst from PSR 1119-6127
- GRB 160703, GRB 160705, GRB 160720, SGR1935+2154: First SGRs and GRBs detected by Lomonosov.
- SGR 1935+2154: CALET Gamma-Ray Burst Monitor detections
- Konus-Wind observation of a bright burst from SGR 1935+2154
- SGR 1935+2154: AMI 15 GHz upper limits of the magnetar during outburst
- Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
- Swift-BAT refined analysis on the bright event from SGR 1935+2154
- Trigger 701590: Swift detection of a bright outburst from SGR 1935+2154
- GROND observations of GRB 160622A/SNR RCW 103/SGR 1617-5103
- Trigger 701182: Swift detection of SGR 1935+2154
- SGR 1617-5103 (BAT trigger 700791): Enhanced Swift-XRT position.
- Swift-BAT refined analysis of the recent outburst from SGR 1617-5103 (a.k.a. 1E 161348-5055 and 2E 1613.5-5053)
- Fermi GBM Trigger 160622573 is not a GRB
- GRB 160622A: Swift detection of a possible short GRB or a new SGR
- More FERMI GBM bursts from the magnetar SGR 1935+2154
- SGR 1935+2154: MAXI/GSC detection
- Fermi GBM trigger 488128598/160620637 is not a GRB
- Fermi GBM trigger 487974449/160618852 is not a GRB
- Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis
- Trigger 689353: Swift detection of a transient near Sgr A*
- Fermi GBM trigger 486562774/160602514 is not a GRB
- Another Swift detection of SGR 1935+2154 (trigger #687124)
- Swift detection of SGR 1935+2154
- Konus-Wind observation of a bright burst from SGR 1935+2154
- FERMI GBM bursts from the magnetar SGR 1935+2154
- SGR 1935+2154: AbAO optical upper limit
- Fermi GBM triggers of SGR 1935+2154
- Trigger 686761: Swift detection of a bright burst from SGR 1935+2154
- Fermi GBM trigger 485124591/160516868 is not a GRB
- Trigger 686443: Swift detection of SGR 1935+2154
- Fermi GBM trigger 484906918/160514349 is not a GRB
- GRB 160401A: a long GRB detected by INTEGRAL
- SGR 0755-2933, Swift-BAT refined analysis
- Swift detection of a likely new SGR: SGR 0755-2933
- IBAS Alert 7313 is SGR J1935+2154
- GRB 151221A: INTEGRAL detection of a short burst or possible SGR
- Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600
- Swift-BAT probable detection of an outburst from SGR J1819-1600 (AX J1818.8-1559)
- LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
- GRB 150912A: A long GRB detected by INTEGRAL
- SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
- Fermi GBM triggers bn150715759 and bn150715817 are not due to GRBs
- Trigger 649113: Swift detection of SGR 1E 1841-045
- Swift-XRT observations of GRB 150710A
- Swift trigger 642453 is not an astrophysical source
- Konus-Wind observation of a bright burst from SGR 1935+2154
- IPN Triangulation of a bright burst from SGR 1935+2154
- GRB 150301A: Swift-BAT refined analysis
- GRB 150301A: Fermi GBM observation
- GRB 150301A: Swift detection of a short burst or new SGR
- Fermi GBM Observations of SGR 1935+2154