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"32501 results found.
- Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
- LIGO/Virgo/KAGRA S230922q: Updated Sky localization
- Konus-Wind detection of GRB 230919A
- LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
- GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
- LIGO/Virgo/KAGRA S230924an: Updated Sky localization
- LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
- LIGO/Virgo/KAGRA S230922g: Updated Sky localization
- LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
- GRB 230918B: VLT/X-shooter classification of AT 2023tbf (GOTO23aky) as a dwarf nova
- IPN triangulation of GRB 230919A (short)
- LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
- GRB 230919A: Fermi GBM Observation
- Correction to Fermi GBM Statement for Trigger 716527670/230916144
- Fermi GBM Statement for Trigger 716527670/230916144
- GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
- LIGO/Virgo/KAGRA S230920al: Updated Sky localization
- LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
- transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
- GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
- GRB 230919A: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
- AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
- LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
- GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
- LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
- Detection of self-absorbed radio emission from GRB 230812B with the JVLA + uGMRT
- GRB 230918A (short): Glowbug gamma-ray detection
- AT 2023sva: NOT observations of the ZTF candidate afterglow
- GRB 230915A: Fermi GBM observation
- GRB 230812B: Radio observations with the uGMRT
- GRB 230917A: AstroSat CZTI detection
- Swift Triggers 1192480, 1192481, 1192482 and 1192483 are not astrophysical events
- GRB 230911A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
- Fermi-LAT gamma-ray observations of IceCube-230914A
- GRB 230911D: GRBAlpha detection
- Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
- GRB 230906A: optical counterpart
- IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230911A: Swift-XRT afterglow detection
- GRB 230913A: CALET Gamma-Ray Burst Monitor detection
- GRB 230913A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
- LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
- GRB 230913A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
- GRB 230911A: Swift ToO observations
- GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
- Fermi GRB 230913A: Global MASTER-Net observations report
- GRB 230911A: GOTO optical counterpart candidate
- GRB 230908A: CALET Gamma-Ray Burst Monitor detection
- GRB 230911D: NuSTAR Detection of Prompt Emission
- GRB 230911B: AstroSat CZTI detection
- GRB 230911C: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
- GRB 230906A: Chandra detection of the X-ray afterglow
- Swift GRB 230911C: Global MASTER-Net observations report
- GRB 230911D: Fermi GBM observation
- IPN triangulation of GRB 230911D (long)
- GRB 230911D: Fermi-LAT detection
- GRB230911C: LCOGT Optical Upper Limits
- LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
- GRB 230911C: Swift/UVOT Upper Limits
- GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
- GRB 230911C: GOTO optical upper limits
- GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- GRB 230911B: correction to the KW GCN 34659
- Konus-Wind detection of GRB 230811D
- GRB 230911C: Swift detection of a burst
- Fermi GRB 230911B: Global MASTER-Net observations report
- GRB 230906A: BlackGEM upper limits
- GRB 230903A: TESS observations of optical emission
- GRB 230906A: AstroSat CZTI detection
- GRB 230908A: GRBAlpha detection
- Glowbug gamma-ray detection GRB 230905B
- GRB 230906A: Swift/UVOT Upper Limits
- GRID detection of GRB 230827A
- GRB 230818A: radio observation with the VLA
- GRB 230205A: LBT spectroscopy of two host galaxy candidates
- GRB 230906A: Swift-XRT observations
- Konus-Wind detection of GRB 230906A (short)
- IPN triangulation of GRB 230906A (short)
- GRB 230906A: Swift ToO observations
- GRB 230905B: AstroSat CZTI detection
- Fermi GRB 230906A: Global MASTER-Net observations report
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
- GRB 230903A: VLT/X-shooter optical observations
- GRB 230903A: Swift-BAT refined analysis
- Fermi GRB 230903A: Global MASTER-Net observations report
- GRB 230903A: Fermi GBM detection
- GRB 230904B is not a GRB
- Fermi GRB 230904A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
- GRB 230903A: LCOGT Optical Upper Limits
- LIGO/Virgo/KAGRA S230831e: Updated Sky localization