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').
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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 G268556/GW170104: MAXI/GSC observations
- LIGO/Virgo G270580: A third optical transient from CNEOST
- LIGO/Virgo G270580: ATLAS coverage and 4 optical transients
- LIGO/Virgo G270580: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo G270580: Two optical counterpart candidates from CNEOST
- LIGO/Virgo G270580: INTEGRAL search of temporally coincident prompt hard X-ray
- LIGO/Virgo G270580: Swift-XRT sources
- LIGO/Virgo G270580: Swift/BAT data search
- LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
- LIGO/Virgo G270580: Mini-MegaTORTORA follow-up observations
- LIGO/Virgo G270580: Pan-STARRS and ATLAS observations of the skymap
- LIGO/Virgo G270580: Observations of initial skymap by Project Mini-GWAC of SVOM
- LIGO/Virgo G270580: AGILE MCAL and Super-AGILE Observations
- LIGO/Virgo G270580 ANTARES search
- LIGO/Virgo G270580: Identification of a GW Burst Candidate
- LIGO/Virgo G268556: RATIR Observation of iPTF Candidates
- LIGO/Virgo G268556: Swift-XRT observations of iPTF17cw
- LIGO/Virgo G268556: spectra of two nuclear transients PS17fr and PS17er
- LIGO/Virgo G268556: TZAC TAROT network observations with TRE/TCA/TCH
- LIGO/Virgo G268556: Gemini spectra of Pan-STARRS1 transients
- LIGO/Virgo G268556: Early SWASP limits of ATLAS17aeu
- LIGO/Virgo G268556: Additional GROWTH follow up observation of iPTF Optical Transient Candidates
- LIGO/Virgo G268556: VLA follow-up of iPTF17cw
- LIGO/Virgo G268556/GW170104: Campo Imperatore Observatory observations
- LIGO/Virgo G268556: AMI 15 GHz detection of ATLAS17aeu
- LIGO/Virgo G268556: Swift/BAT data search
- LIGO/Virgo G268556: Lijiang Observatory GMG Telescope Upper Limit on ATLAS17aeu
- LIGO/Virgo G268556: Liverpool Telescope Spectroscopy of iPTF17bv and iPTF17ck
- LIGO/Virgo G268556: Spectroscopic observations of ATLAS17aeu and iPTF17cw
- LIGO/Virgo G268556: NOWT of EWE, Xinglong 0.6/0.9m, Xuyi 1m optical upper limits of ATLAS17aeu and a reminder of GCN 20394
- LIGO/Virgo G268556/GW170104: TNG observations of ATLAS17aeu
- LIGO/Virgo G268556: Swift-XRT confirms that ATLAS17aeu is fading in X-rays
- LIGO/Virgo G268556: ATLAS17aeu position is consistent with GRB170105A
- LIGO/Virgo G268556: Liverpool Telescope Spectroscopy of iPTF candidates
- LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
- LIGO/Virgo G268556/GW170104: 10.4m GTC spectroscopic observations of iPTF17fs
- LIGO/Virgo G268556/GW170104: TNG spectroscopic observations of iPTF17ck and iPTF17dz
- LIGO/Virgo G268556: Gemini spectrum and Pan-STARRS observations of ATLAS17aeu
- LIGO/Virgo G268556: IPN Triangulation of GRB 170105A (association with ATLAS17aeu)
- LIGO/Virgo G268556: GWAC_F60B (60cm) follow-up two events of EWE001 and EWE002
- LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
- LIGO/Virgo G268556: Continued iPTF Observations and Additional Optical Transient Candidates
- LIGO/Virgo G268556: Swift/UVOT observations of ATLAS17aeu
- LIGO/Virgo G268556: CALET Observations
- LIGO/Virgo G268556: iPTF Optical Transient Candidates
- LIGO/Virgo G268556: VLA follow-up of ATLAS17aeu
- LIGO/Virgo G268556: AGILE-GRID preliminary analysis
- LIGO/Virgo G268556: EWE001 and EWE002- two events close to GCN 20382 with the skymap
- LIGO/Virgo G268556: Palomar 200-inch detects ATLAS17aeu, possible afterglow of GRB070105A?
- LIGO/Virgo G268556/GW170104: Global MASTER Net second OT detection
- LIGO/Virgo G268556: Swift-XRT detection of ATLAS17aeu
- LIGO/Virgo G268556: SWASP optical imaging
- LIGO/Virgo G268556/GW170104: Asiago Observations
- LIGO/Virgo G268556: Updated sky map from gravitational-wave data
- LIGO/Virgo G268556: HAWC follow-up of northern sky
- LIGO/Virgo G268556: Pan-STARRS1 observations of the skymap
- LIGO/Virgo G268556: ATLAS17aeu - an unusual transient within the skymap
- LIGO/Virgo G268556/GW170104: Global MASTER Net observations and first OT detection
- LIGO/Virgo G268556: ATLAS imaging of the skymap
- LIGO/Virgo G268556: DESGW/DECam observations
- LIGO/Virgo G268556: AGILE MCAL and Super-AGILE Observations
- LIGO/Virgo G268556: Fermi-LAT search for high-energy gamma-ray counterpart
- LIGO/Virgo G268556: Mini-MegaTORTORA follow-up observations
- LIGO/Virgo G211117 / GW151226: LOFAR follow-up
- LIGO/Virgo G268556: Swift-XRT sources
- LIGO/Virgo G268556: ANTARES search
- LIGO/Virgo G268556: observation regions by Project Mini-GWAC of SVOM
- LIGO/Virgo G268556: INTEGRAL search of temporally coincident prompt hard X-ray emission
- LIGO/Virgo G268556: Fermi GBM Observations
- LIGO/Virgo G268556: Identification of a GW CBC Candidate
- Fermi GBM Observations of IceCube-161103
- GRB 160927A: NOT optical observations
- IPN Triangulation of GRB 160822A (short/hard)
- IPN Triangulation of GRB 160820A (short/hard)
- Fermi GBM Observations of IceCube-160806A
- LIGO/Virgo G211117 / GW151226: Sky maps and other data available in LOSC
- LIGO/Virgo G197392 / LVT151012: Sky maps and other data available in LOSC
- LIGO/Virgo G211117/GW151226: serendipitous XMM-Newton slew observations
- LIGO/Virgo G211117: Astrosat CZTI upper limits
- IceCube-160427A: Fermi GBM Observations
- LIGO/Virgo G197392 / LVT151012: Identification of a GW CBC Candidate
- LIGO/Virgo G211117: EWE for NOWT of 12 days follow-up of northern sky
- LIGO Virgo G211117: Additional MWA Observations
- IPN Triangulation of GRB 160406A (short/hard)
- LIGO/Virgo G211117: 10.4m GTC follow-up of PS15dpn
- LIGO/Virgo G211117: LOFAR follow-up
- LIGO/Virgo G211117: CALET GBM Observations
- LIGO/Virgo G211117: EWE for NOWT follow-up of northern sky
- LIGO/Virgo G194575: EWE for NOWT follow-up of northern sky
- LIGO/Virgo G211117: HAWC follow-up of northern sky
- LIGO/Virgo G211117: GRAWITA LBT follow-up of PS15dpn
- IPN Triangulation of GRB 160225B
- IPN Triangulation of GRB 160219A (short/hard)
- LIGO/Virgo GW150914
- LIGO/Virgo GW150914: BOOTES-3 simultaneous imaging
- LIGO/Virgo G184098: MASTER arhival results
- LIGO/Virgo G184098: Correction for GCN Circular 18361
- LIGO/Virgo G184098: MAXI/GSC search for an X-ray counterpart of GW150914
- LIGO/Virgo G211117: LOFAR follow-up
- LIGO Virgo G211117: MWA Observations