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"4055 results found.
- LIGO/Virgo S200213t: No transient candidates in CALET observations
- LIGO/Virgo S200213t: Lulin Follow-Up Observations
- GRB 200215A: Nanshan/NEXT optical upper limit
- 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 S200213t: DBSP spectroscopy of AT2020cjb/ZTF20aamvnth, AT2020cja/ZTF20aamvmzj, AT2020cjc/ZTF20aamvoeh
- LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
- LIGO/Virgo S200213t: MASTER OT detection in PGC673735
- LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
- 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: No Counterparts from GECKO observation of host galaxy candidates in GW-neutrino detection overlap area
- LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
- LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
- LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
- LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
- LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200213t: AT2020ciy/ZTF20aamvqxl, AT2020cjg/ZTF20aamvoxx and AT2020cje/ZTF20aamvtip 10.4m GTC spectroscopy
- LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
- LIGO/Virgo S200213t: Swift/BAT in the South Atlantic Anomaly
- LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
- LIGO/Virgo S200213t: not observable by Fermi-GBM
- LIGO/Virgo S200213t: upper limits from AGILE/GRID 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: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
- LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200213t: Neutrino and galaxies cross-match
- LIGO/Virgo trigger S200213t: Possible host galaxies
- 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 S200213t: Global MASTER-Net observations report
- LIGO/Virgo S200208q: Updated Sky Localization
- LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
- LIGO/Virgo S200208q: Not observable by CALET
- LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
- LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200208q: Global MASTER-Net observations report
- 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
- LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
- LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
- AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-200202A
- LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
- LIGO/Virgo S200129m: Upper limits from CALET observations.
- LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200129m: NED Galaxies in the 50% Localization Volume
- LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200129m: Not observable by Fermi-GBM
- LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
- LIGO/Virgo S200129m: Global MASTER-Net observations report
- LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
- LIGO/Virgo S200129m: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
- LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
- LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200128d: Upper limits from CALET observations
- LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
- LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
- Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
- LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- 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
- LIGO/Virgo S200128d: Global MASTER-Net observations report
- LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
- LIGO/Virgo S191222n: AstroSat CZTI upper limits
- LIGO/Virgo S200112r: AstroSat CZTI upper limits
- LIGO/Virgo S200114f: AstroSat CZTI upper limits
- LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
- LIGO/Virgo S200115j: Further Swift-XRT sources
- LIGO/Virgo S200115j: Upper limits from Konus-Wind observations
- LIGO/Virgo S200114f: Upper limits from Konus-Wind observations
- LIGO/Virgo S200112r: Upper limits from Konus-Wind observations
- LIGO/VIRGO S200115j: No obvious candidates from Pan-STARRS2 observations
- LIGO/Virgo S200105ae: Upper limits from Konus-Wind observations
- LIGO/Virgo S191222n: Upper limits from Konus-Wind observations
- LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations
- LIGO/Virgo S191215w: Upper limits from Konus-Wind observations