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"7450 results found.
- LIGO/Virgo S200219ac: AstroSat CZTI upper limits
- LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
- GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
- GRB 200228B: KAIT Optical Upper Limit
- LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
- IceCube-200227A : Upper limits from Insight-HXMT/HE observations
- HAWC-200216A: No Neutrino Counterpart in ANTARES Search
- IceCube-200227A: Upper limits from Fermi-GBM Observations
- IceCube-200227A: IceCube observation of a high-energy neutrino candidate event
- GRB 200227A: Swift detection of a burst
- LIGO/Virgo S200225q: Not observable by CALET
- LIGO/Virgo S200224ca: Upper limits from CALET observations.
- LIGO/Virgo S200225q: Updated Sky Localization
- LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
- LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200219ac: Updated Sky Localization
- LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
- LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
- LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
- LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
- GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
- LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
- GRB 200219C: Swift-XRT afterglow confirmation
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
- GRB 200219C: Mondy and TSHAO optical observations
- GRB 200219C: DDOTI Observations
- GRB 200219C: Tiled Swift observations
- LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
- LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
- LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
- LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
- GRB 200219A: MASTER catalog automatic possible Host Galaxy candidate
- GRB 200219A: Swift detection of a short burst
- LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
- GRB 200216B - possible IR counterpart from VLT
- LIGO/Virgo S200213t: AstroSat CZTI upper limits
- GRB 200216B: Swift detection of a burst
- LIGO/Virgo S200213t: Updated Sky Localization
- LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
- LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
- LIGO/Virgo S200213t: Updated Sky Localization
- LIGO/Virgo S200213t: Lulin Follow-Up Observations
- GRB 200215A: Swift detection of a burst
- LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
- LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
- LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
- LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
- LIGO/Virgo S200213t: No notable candidates in GOTO imaging
- LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
- LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
- LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
- LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200213t: Neutrino and galaxies cross-match
- LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
- LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
- LIGO/Virgo S200208q: Updated Sky Localization
- LIGO/Virgo S200208q: Not observable by CALET
- LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
- LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
- LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
- Swift Trigger 954840 is not a GRB
- GRB 200205B: Swift detection of a burst with optical counterpart
- AMON IceCube-HAWC_200202A : No neutrino counterpart seen with ANTARES
- GRB 200131A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200129m: Upper limits from CALET observations.
- LIGO/Virgo S200129m: NED Galaxies in the 50% Localization Volume
- LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
- LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
- LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
- LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
- LIGO/Virgo S200128d: Identification of a GW compact binary merger candidate
- LIGO/Virgo S200128d: Upper limits from IceCube neutrino searches
- GRB 200127A: Swift detection of a burst
- GRB 200125A: AbAO optical upper limit
- GRB 200125A: TNG detection of a NIR counterpart candidate
- GRB 200115A: Assy optical observations
- LIGO/Virgo S191222n: AstroSat CZTI upper limits
- LIGO/Virgo S200112r: AstroSat CZTI upper limits
- LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
- IPN Triangulation of GRB 200120A
- GRB 200122A: GOTO non-detection of optical afterglow
- GRB 200122A: Swift detection of a burst
- IceCube-200120A: not observable by Fermi-GBM