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"7445 results found.
- LIGO/Virgo/KAGRA S231008ap: Updated Sky localization
- LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231005ah: Updated Sky localization
- LIGO/Virgo/KAGRA S231005ah: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231005j: Updated Sky localization
- LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
- IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
- transient AT2023sva: radio observations with AMI-LA
- LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
- LIGO/Virgo/KAGRA S230930al: Updated Sky localization
- LIGO/Virgo/KAGRA S230928cb: Updated Sky localization
- LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
- AT2023sva / GRB230916B: GIT observations of the afterglow
- transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
- LIGO/Virgo/KAGRA S230927be: Updated Sky localization
- LIGO/Virgo/KAGRA S230927l: Updated Sky localization
- LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230922q: Updated Sky localization
- LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
- 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 S230904n: Classification of the candidate AT2023rkw with DBSP
- Correction to Fermi GBM Statement for Trigger 716527670/230916144
- Fermi GBM Statement for Trigger 716527670/230916144
- LIGO/Virgo/KAGRA S230920al: Updated Sky localization
- LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
- 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
- AT 2023sva: NOT observations of the ZTF candidate afterglow
- ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
- LIGO/Virgo/KAGRA S230918aq: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
- LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
- LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
- GRB 230911A: Swift-XRT afterglow detection
- LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
- IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
- GRB 230911A: Swift ToO observations
- GRB 230911A: GOTO optical counterpart candidate
- LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
- GRB 230906A: Chandra detection of the X-ray afterglow
- LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
- GRB 230911C: GOTO optical upper limits
- LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
- GRB 230205A: LBT spectroscopy of two host galaxy candidates
- GRB 230906A: Swift ToO observations
- GRB 230812B: Chandra late-time detection of the X-ray afterglow
- LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
- GRB 230903A: Swift detection of a burst
- LIGO/Virgo/KAGRA S230831e: Updated Sky localization
- LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230715bw: Reissue of Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230830b: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230820bq: Updated Sky localization
- GRB 230827B: Swift ToO observations
- LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
- GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
- GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
- AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
- GRB 230826A: Mondy optical observations
- LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
- NICER detection of Swift J1727.8-1613 (GRB 230824A)
- LIGO/Virgo/KAGRA S230825k: Updated Sky localization
- LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
- GRB 230824A: AKO Optical Afterglow Candidate
- LIGO/Virgo/KAGRA S230824r: Updated Sky localization
- LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
- IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
- LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
- LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
- GRB 230818A: Swift detection of a burst
- GRB 230816A: Swift detection of a burst
- GRB 230815A: Swift detection of a burst
- GRB 230812B: AMI-LA radio detection of afterglow candidate
- LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230814r: Updated Sky localization
- GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
- GRB 230812B: GIT optical follow-up