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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
5468 results found.
- ZTF23aaoohpy/AT2023lcr: SAO RAS observations
- ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
- AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
- ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
- GRB 230618A: Swift-XRT refined Analysis
- GRB 230616A: Swift-XRT observations
- LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
- GRB 230614B: Fermi GBM Observation
- GRB 230614C: Fermi GBM Detection
- ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
- GRB 230506B: Chandra localization of the X-ray afterglow
- GRB 230606A: Fermi GBM Observation
- GRB 230606A: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-230603A
- LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Alert from the HAWC Burst Monitor HAWC-230527A
- Fermi-LAT gamma-ray observations of IceCube-230524A
- GRB 230525A: Fermi GBM Detection
- GRB 230524A: Fermi GBM Observation
- GRB 230518A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
- LIGO/Virgo S230518h: AGILE/MCAL observations
- LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
- LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
- GRB 230510B: Fermi GBM detection
- GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
- Fermi-LAT gamma-ray observations of IceCube-230511A
- GRB 230512A: Swift-XRT observations
- GRB 230512A: GIT optical follow-up ZTF candidates
- GRB 230512A: Fermi GBM detection
- GRB 230512A: Fermi-LAT detection
- GRB 230510A: GIT optical upper limits
- GRB 230510A: Fermi GBM detection
- GRB 230506B: Fermi GBM detection
- GRB 230510A: Swift-XRT refined Analysis
- GRB 230506C: Fermi GBM detection
- GRB 230506C: SAO RAS optical observations
- Fermi-LAT gamma-ray observations of IceCube-230506A
- GRB 230506C: Swift-XRT refined Analysis
- GRB 230506C: Swift/UVOT Upper Limits
- GRB 230506B: Swift-XRT refined Analysis
- GRB 230506C: Swift-XRT analysis
- GRB 230430A: Fermi GBM observation
- GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
- GRB 230427A: Swift-XRT refined Analysis
- GRB 230427A: GIT optical upper limit
- GRB 230426A: Fermi GBM Detection
- GRB 230423A: Swift-XRT refined Analysis
- GRB 230421A: Fermi GBM observation
- GRB 230420A: Swift-XRT refined Analysis
- GRB 230420A: NOT optical afterglow confirmation
- GRB 230402A: Fermi GBM detection
- GRB 230418A: Fermi GBM Observation
- GRB 230402A: Fermi-LAT detection
- Fermi-LAT gamma-ray observations of IceCube-230416A
- GRB 230415A: Fermi GBM detection
- GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
- GRB 230307A: iTelescope optical upper limit (likely)
- GRB 230414B: Lulin 40cm-SLT optical limit
- GRB 230414B: Swift-XRT refined Analysis
- GRB 230414B: 1.3m DFOT Optical observations
- GRB 230328B: redshift lower limit estimating
- GRB 230409B: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-230405A
- GRB 230405B: Swift-XRT refined Analysis
- GRB 230405B: Fermi GBM Observation
- GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
- Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
- GRB 230307A: Chandra late-time detection of the X-ray afterglow
- GRB 230328B: 3.6m DOT multiband optical observation
- GRB 230328B: Swift-XRT refined Analysis
- GRB 230328B: Fermi GBM observation
- GRB 230325A: Swift-XRT refined Analysis
- GRB 230320B: Fermi GBM Observation
- GRB 230322B: Swift-XRT refined Analysis
- GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
- GRB 230307A: Swift/UVOT detection
- GRB 230307A: Swift-XRT afterglow detection
- Alert from the HAWC Burst Monitor HAWC-230311A
- GRB 230308A: Fermi GBM detection
- GRB 230307A: ASO-S/HXI detection
- GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
- GRB 230307A: Swift/BAT upper limits on the early afterglow
- GRB 230307A: Swift-XRT observations
- GRB 230307A: AstroSat CZTI detection
- Fermi-LAT gamma-ray observations of IceCube-230306A
- GRB 230228A: Swift-XRT refined Analysis
- GRB 230217A: Swift/UVOT Upper Limits
- GRB 230217A: Swift-XRT afterglow detection
- Fermi-LAT gamma-ray observations of IceCube-230220A
- GRB 230217A: Gemini-South Optical Observation
- GRB 230217A: Fermi GBM observation
- Fermi-LAT gamma-ray observations of IceCube-230217A
- GRB 230217A: Swift-XRT observations
- GRB 230216A: Swift-XRT refined Analysis
- GRB 230209B: Fermi GBM Observation
- Swift Trigger 1153670 is probably not a GRB
- GRB 221009A: Continued Swift Observations
- GRB 230204B: Swift/UVOT Upper Limits