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"28050 results found.
- GRB 230802A: Swift detection of a burst
- IceCube-230724A: JCMT/SCUBA-2 submm observations
- IceCube-230707A: JCMT/SCUBA-2 submm observations
- LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
- LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230729z: Updated Sky localization
- GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
- Fermi trigger No 712390645: Global MASTER-Net observations report
- GRB 230728A: Swift-BAT refined analysis
- Fermi-LAT gamma-ray observations of IceCube-230727A
- GRB 230723B: Swift-BAT refined analysis
- Fermi trigger No 712306969: Global MASTER-Net observations report
- GRB 230723B: MITSuME Ishigaki optical observation
- LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
- IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230728A: BOOTES-1 optical upper limit
- GRB 230728A: Fermi GBM Observation
- GRB 230728A: LCOGT Optical Upper Limit
- GRB 230728A: Swift/UVOT Upper Limits
- GRB 230728A: Swift-XRT refined Analysis
- GRB 230728A: Enhanced Swift-XRT position
- GRB 230728A: NOT optical observations and possible host galaxy
- GRB 230728A: Swift detection of a burst
- GRB 230727A: Swift/BAT-GUANO detection of a burst
- Fermi-LAT gamma-ray observations of IceCube-230725A
- Fermi-LAT gamma-ray observations of IceCube-230724A
- IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230723B: Further CAHA observations and host galaxy detection
- LIGO/Virgo/KAGRA S230726a: Updated Sky localization
- GRB 230723B: MITSuME Akeno optical afterglow candidate detection
- LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
- GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
- GRB 230723B: Leavitt Observatory upper limit
- GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
- GRB 230723B: Montarrenti Observatory upper limit
- GRB 230723B: Optical afterglow candidate from CAHA
- GRB 230723B: Bassano Bresciano Observatory upper limit
- GRB 230723B: Fermi GBM observation
- GRB 230723B: Swift-XRT refined Analysis
- GRB 230723B: non-detections from Observatoire de Haute-Provence
- LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
- GRB 230723B: Optical limit from CAHA
- GRB 230723B: Swift/UVOT Upper Limits
- GRB 230723B: Swift-XRT observations
- LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
- GRB 230723B: Swift detection of a burst
- IPN triangulation of GRB 230715D
- Swift Trigger 1180055 is not a GRB
- LIGO/Virgo/KAGRA S230708z: Updated Sky localization
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
- LIGO/Virgo/KAGRA S230708t: Updated Sky localization
- GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
- IceCube-230708A: Upper limits from Swift/BAT-GUANO
- GRB 230709C: GRBAlpha detection
- GRB 230707B: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
- IceCube-230707A: No candidates detected by Swift-XRT
- LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
- GRB 230703A detected with multiple GRID detectors
- GRB 230709C: BALROG localization (Fermi Trigger 710617111 / GRB 230709735)
- LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
- Fermi-LAT gamma-ray observations of IceCube-230708A
- Fermi-LAT gamma-ray observations of IceCube-230707B
- Fermi-LAT gamma-ray observations of IceCube-230707A
- LIGO/Virgo/KAGRA S230630am: Updated Sky localization
- LIGO/Virgo/KAGRA S230630am: Updated Sky localization
- GRB 230709B: BALROG localization (Fermi Trigger 710614579 / GRB 230709706)
- IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
- IceCube-230707A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
- GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 230707A: Swift-XRT observations
- GRB 230707A: Fermi GBM Detection
- LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
- GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
- LIGO/Virgo/KAGRA S230706ah: Updated Sky localization
- LIGO/Virgo/KAGRA S230704f: Updated Sky localization
- LIGO/Virgo/KAGRA S230630bq: Updated Sky localization
- LIGO/Virgo/KAGRA S230702an: Updated Sky localization
- LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
- ZTF23aaoohpy/AT2023lcr: AMI-LA radio detection
- Fermi trigger No 710117592: Global MASTER-Net observations report
- GRB 230626A: VZLUSAT-2 detection
- LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
- GRB 230328B: LBT detection of the likely host galaxy
- LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate
- GRB 230701B: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
- LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate