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"
2722 results found.
- LIGO/Virgo S200114f: Candidates from the Zwicky Transient Facility
- LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
- Fermi trigger No 600227156: Global MASTER-Net observations report
- Swift GRB200109.07: Global MASTER-Net observations report
- GRB 200109A: Swift detection of a burst
- LIGO/Virgo S200105ae: Candidates from the Zwicky Transient Facility
- GRB 200107B: Fermi GBM observation
- IceCube-200107A: No candidates from the Zwicky Transient Facility
- LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
- LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200105ae: Global MASTER-Net observations report
- LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Fermi trigger No 599761015: Global MASTER-Net observations report
- IceCube Alert 200101.46: Global MASTER-Net observations report
- IPN triangulation of GRB 191227B (short)
- Fermi trigger No 598988276: Global MASTER-Net observations report
- LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191216ap: No significant candidates found in Pan-STARRS observations
- LIGO/Virgo S191222n: no counterpart candidates in the Swift/BAT observations
- Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
- Fermi trigger No 598648473: Global MASTER-Net observations report
- LIGO/Virgo S191216ap: MASTER optical observation
- LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
- LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S191216ap: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191216ap: No Candidates from the Zwicky Transient Facility
- LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S191216ap: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S191215w: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191215w: Global MASTER-Net observations report
- LIGO/Virgo S191213g: Additional candidates from the Zwicky Transient Facility
- LIGO/Virgo S191213g: Lulin Follow-up Observations of ZTF19acykzsk/AT2019wqj
- LIGO/Virgo S191213g: Candidates from the Zwicky Transient Facility
- LIGO/Virgo S191213g: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
- LIGO/Virgo S191205ah: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
- LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
- LIGO/Virgo S191205ah: Global MASTER-Net observations report
- LIGO/Virgo S191204r: no counterpart candidates in the Swift/BAT observations
- IceCube Alert 191204.95: Global MASTER-Net observations report
- GRB 191203A: Fermi GBM Final Real-time Localization
- Fermi trigger No 596786686: Global MASTER-Net observations report
- Fermi trigger No 596808579: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 191127.25: Global MASTER-Net observations report
- LIGO/Virgo S191124be: Global MASTER-Net observations report
- IceCube-191119A: No significant detection in HAWC
- LIGO/Virgo S191110af: Upper limits from IceCube MeV neutrino searches
- LIGO/Virgo S191110af: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
- LIGO/Virgo S191109d: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S191105e: no counterpart candidates in the Swift/BAT observations
- Fermi trigger No 594592184: Global MASTER-Net observations report
- Trigger 933276: Swift detection of further activity from SGR 1935+2154
- GRB 191101A: Swift-BAT refined analysis
- Fermi trigger No 594563923: Global MASTER-Net observations report
- Fermi trigger No 594557071: Global MASTER-Net observations report
- GRB 191031D: Zwicky Transient Facility Follow-Up of a Swift Short GRB (Trigger 594249816/191031891)
- GRB 191101A: Prompt enhanced Swift-XRT position
- GRB 191031D: COATLI Optical Observations
- IPN triangulation of GRB 191025B (short)
- GRB 191023A: MASTER optical observation
- Possible GRB 191025A: FRAM-Auger optical limit
- Swift Trigger 931384: possible GRB 191025A
- Fermi trigger No 592818648: Global MASTER-Net observations report
- ANTARES 191011A: MASTER optical observation befor and after trigger
- GRB 191011A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
- Konus-Wind observation of GRB 191004B
- GRB 191004A: Optical Detection with LCO
- LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
- LIGO/Virgo S190930t: Magellan/IMACS imaging of Swift J224718-581442 (AT2019sbk)
- LIGO/Virgo S190930t: Swift discovery of Swift J224718-581442 (AT2019sbk): a fading UV transient with an X-ray counterpart
- LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
- GRB 191001B: Optical Upper Limits with LCO
- IceCube-191001A: Candidate Counterparts with the Zwicky Transient Facility
- LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
- LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
- LIGO/Virgo S190930t: Candidates from the Zwicky Transient Facility
- Fermi trigger No 591604915: Global MASTER-Net observations report
- LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Fermi trigger No 591391412: Global MASTER-Net observations report
- Fermi trigger No 591321287: Global MASTER-Net observations report
- LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
- IceCube-190922B: Identification of a Candidate Supernova from the Zwicky Transient Facility
- LIGO/Virgo S190923y: Upper limits from IceCube neutrino searches