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.
- GRB 200416A: Swift detection of a burst with an optical afterglow
- Konus-Wind observation of GRB 200412A
- Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
- Swift GRB 200409A: Global MASTER-Net observations report
- Fermi GRB 200407A: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
- Fermi GRB 200405A: Global MASTER-Net observations report
- Fermi GRB 200403B: Global MASTER-Net observations report
- Fermi GRB 200403A: Global MASTER-Net observations report
- Fermi GRB 200402C: Global MASTER-Net observations report
- Fermi GRB 200401A: Global MASTER-Net observations report
- GRB 200325B: Mondy continued observations
- Fermi trigger No 606918292: Global MASTER-Net observations report
- GRB 200326A: Fermi GBM Final Real-time Localization
- Fermi trigger No 606681997: Global MASTER-Net observations report
- LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
- Fermi trigger No 606263732: Global MASTER-Net observations report
- LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
- SGR Swift J1818.0-1607: BOOTES-4/MET optical limit
- Fermi trigger No 605756501: Global MASTER-Net observations report
- Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
- Fermi trigger No 605632577: Global MASTER-Net observations report
- GRB 200310A: MAXI/GSC detection
- LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
- GRB 200303A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
- LIGO/Virgo S200302c: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200224ca: Transient found in Swift/UVOT counterpart search
- LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
- GRB 200227A: Mondy optical upper limit
- LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
- LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
- LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
- GRB 200224B: DDOTI/OAN optical observations report
- LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
- LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
- Fermi trigger No 604231129: Global MASTER-Net observations report
- GRB 200224C: Fermi GBM Final Real-time Localization
- GRB 200223A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
- LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
- LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
- GRB 200216B: Mondy and AbAO optical upper limits
- LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
- LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
- LIGO/Virgo S200213t: No notable candidates in GOTO imaging
- LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
- LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
- LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
- LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
- LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
- LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
- LIGO/Virgo trigger S200213t: Possible host galaxies
- GRB 200131A: Tautenburg observations
- LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
- LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
- Fermi trigger No 602817262: Global MASTER-Net observations report
- GRB 200205B: Swift-BAT refined analysis
- Fermi trigger No 602731380: Global MASTER-Net observations report
- Fermi trigger No 602626648: Global MASTER-Net observations report
- GRB 200205C: Fermi GBM Final Real-time Localization
- ZTF20aajnksq: Occulted by Earth at the time of GRB 200128A
- ZTF Discovery of ZTF20aajnksq: a Rapidly Fading Luminous Transient in the GRB 200128A Localiziation Region
- LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
- Fermi trigger No 602071201: Global MASTER-Net observations report
- Fermi trigger No 602056641: Global MASTER-Net observations report
- LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
- LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
- GRB 200125B: DDOTI/OAN optical observations report
- Fermi trigger No 601841483: Global MASTER-Net observations report
- Fermi trigger No 601729856: Global MASTER-Net observations report
- Fermi trigger No 601677816: Global MASTER-Net observations report
- LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
- GRB 200122A: MITSuME Akeno optical upper limits
- Fermi trigger No 601363105: Global MASTER-Net observations report
- Konus-Wind observation of GRB 200120A
- Fermi trigger No 601254300: Global MASTER-Net observations report
- IceCube Alert 200120.78: Global MASTER-Net observations report
- LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
- IceCube-200117A: One Additional Candidate Counterpart from the Zwicky Transient Facility
- IceCube-200117A: Candidate Counterpart from the Zwicky Transient Facility
- LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
- LIGO/Virgo S200114f: More candidates from the Zwicky Transient Facility
- LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200115j: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200115j: Candidates from the Zwicky Transient Facility
- LIGO/Virgo trigger S200115j: Possible host galaxies
- LIGO/Virgo S200114f: no counterpart candidates in the Swift/BAT observations
- IceCube-200109A: Candidate Counterparts from the Zwicky Transient Facility