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.
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subject:"Swift"body:"GRB"submitter:"Judith Racusin"24392 results found.
- Integral GRB250211.89: Global MASTER-Net observations report
- GRB 250212A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S250211be: Updated Sky localization
- GRB 250207A: Fermi GBM Observation
- GRB 250206A: Fermi GBM Observation
- IceCube-250207A: One candidate from the Zwicky Transient Facility
- EP250207b: Tentative z-band brightening source
- LIGO/Virgo/KAGRA S250206dm: continued in SOAR galaxy targeted observations and identification of one possible transient
- Konus-Wind detection of GRB 250207A
- Konus-Wind detection of GRB 250206A
- EP250207b: Global MASTER-Net observations report
- Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082)
- LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
- EP250207b: Gemini GMOS-N z-band observations
- EP250207A: Upper limits from Fermi-GBM Observations
- EP250207b: a new X-ray transient detected by Einstein Probe
- Fermi GRB 250210A: Global MASTER-Net observations report
- GRB 250210A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
- IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
- IceCube Alert 250207.09: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
- GRB 250204B: GRBAlpha detection
- GRB 250204A: GRBAlpha detection
- LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy
- Fermi-LAT Gamma-ray Observations of IceCube-250207A
- GRB 250207A: 1.3m DFOT Optical observations
- LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
- GRB 250206A: Swift-XRT observations
- GRB 250207A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
- LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
- GRB 250205A: 1.3m DFOT optical upper limit
- LIGO/Virgo/KAGRA S250118az: Updated Sky localization
- LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
- GRB 250206A: EIRSAT-1 GMOD Detection
- LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
- GRB 250206A: Fermi-LAT detection
- GRB 250207B: Swift-XRT observations
- LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
- IceCube-250203A: No transient candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS
- LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
- GRB 250208A: Fermi GBM Final Real-time Localization
- EP250207a: EP-WXT detection and XRT follow-up observation
- LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
- GRB 250207A: Swift-XRT refined Analysis
- LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
- CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
- LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
- EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
- GRB 250129A: ABObservatory SLOAN r’ afterglow detection
- GRB 250207A: REM IR afterglow detection
- LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
- LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
- Konus-Wind detection of GRB 250204B
- IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 250207A: REM optical afterglow detection
- LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
- LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
- LIGO/Virgo/KAGRA S250206dm: SOAR galaxy targeted observations
- LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
- LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
- LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
- GRB 250207A: Fermi GBM Final Real-time Localization
- Fermi-LAT Gamma-ray Observations of IceCube-250203A
- LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
- LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
- GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
- GRB 250206A: Fermi GBM Final Real-time Localization
- GRB 250205A: Fermi GBM Observation
- GRB 250205A: REM NIR upper limit
- LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
- EP250205a/GRB 250205A: correction to the source localization
- EP250205a/GRB 250205A: Einstein Probe observation
- GRB 250127C: SVOM/GRM observation of a burst
- GRB250205A: SVOM/VT optical afterglow detection
- GRB 250205A: GOTO optical upper limits
- LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
- GRB 250205A: SVOM detection of a burst
- LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
- Konus-Wind detection of GRB 250201A
- IPN triangulation of GRB 250201A
- LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
- Konus-Wind detection of GRB 250202B