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').
10043 results found.
- GRB 241025C: VZLUSAT-2 detection
- GRB 241025A: VZLUSAT-2 detection
- GRB 241018A: cubesat Avion detection
- LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
- INTEGRAL detection of a burst from 1E 1841-045
- EP241107a: AbAO optical upper limit
- EP241107a: Kinder optical follow-up observations
- GRB 241025A: radio detection with the VLA
- GRB 241104A: CALET Gamma-Ray Burst Monitor detection
- GRB 241105A: ePESSTO+ NTT optical afterglow detection
- EP241101a: CrAO ZTSH optical observations
- GRB 241030A: Mondy optical observations
- GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
- GRB 241104A/EP241104a: Optical upper limits with Kinder observations
- GRB 241010A: host galaxy redshift z = 0.977
- GRB 240821A: further radio observations with the VLA
- GRB 241030A: GRBAlpha detection
- EP241101a: EP-FXT observations update
- EP241103a: GOTO optical upper limit
- EP241101a: Optical upper limits with Kinder observations
- LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
- GRB 241029A: GRBAlpha detection
- Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
- EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
- EP241101a: EP-WXT detection of a fast X-ray transient
- GRB 241026A: SAO RAS optical observations
- EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
- GRB 241030B: Swift-BAT refined analysis
- GRB 241030A: Swift-BAT refined analysis
- GRB 241030B: Swift/UVOT Detection
- GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
- GRB 241030B : MITSuME Akeno optical upper limits
- EP241030a: EP detection of GRB 241030A X-ray Afterglow
- GRB241030B: Fermi GBM Observation
- GRB 241030B: BTA observations
- EP241021a: Swift-UVOT detection
- GRB241030B: GRANDMA/TAROT Upper Limit
- GRB 241030B: SAO RAS optical observations
- GRB 241030B: Swift detection of a burst
- GRB 240912A: radio detection with the VLA
- Swift GRB 241030A: Global MASTER-Net observations report
- GRB 241030A: Swift/UVOT Detection
- EP 241021a: further Swift-XRT observations and X-ray counterpart detection
- GRB 241030A : MITSuME Akeno optical afterglow detection
- GRB 241030A: Swift detection of a burst with a bright optical counterpart
- GRB 241026A: SAO RAS optical observations
- GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
- GRB 240821A: Keck/LRIS spectroscopic observations
- GRB 241026A: the 100th GRB detected by GRBAlpha
- GRB 241025A: Swift/UVOT Detection
- GRB 241025A: Mondy optical observations
- GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
- EP241021a: optical follow-up observations with the Liverpool Telescope
- GRB 241025A: NOT spectroscopic redshift of z = 4.20
- EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
- GRB 241010A: VIRT Optical Upper Limit
- EP241021a: Optical counterpart observations with the Liverpool Telescope
- EP241021a: Optical upper limits with Kinder observations
- GRB 241018A: EP-FXT afterglow detection
- EP241021a: GOTO optical upper limits
- GRB 241018A: Mondy optical upper limit
- GRB 241006A: VIRT Optical Upper Limit
- GRB 240727A: VIRT Optical Upper Limit
- GRB 241018A: X-ray afterglow candidate observed by MXT
- GRB 241001A: EP-FXT afterglow detection
- GRB241017A: TOO Observations by SVOM/MXT
- GRB 240916A: radio detection with the VLA
- GRB 241009A: GRANDMA optical upper limits
- GRB 241006A: GRANDMA optical upper limits
- EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
- GRB 240821A: Host galaxy redshift from VLT/X-shooter
- GRB 240930B: CALET Gamma-Ray Burst Monitor detection
- GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
- GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
- GRB 241002C : MITSuME Akeno optical upper limits
- GRB 241002A: Swift/UVOT Upper Limits
- GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
- EP trigger ID 01709064214: the X-ray transient is most likely a stellar flare event
- GRB 240930B: GRBAlpha detection
- GRB 240929A: GRBAlpha detection
- EP240930a: EP-FXT follow-up observation update
- EP240930a: EP-WXT detection of a fast X-ray transient
- EP240918b and EP240918c: EP-FXT follow-up observations
- GRB 240905B: VZLUSAT-2 detection
- LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
- EP240919a: EP-FXT follow-up observation update
- EP240913A/GRB 240913C: AbAO optical upper limit
- EP240919a / GRB 240919A: Mondy optical upper limit
- GRB 240414A: further radio observations with the VLA
- GRB 240910A: radio detection with the VLA
- EP240919a: NOT and Gemini optical observations
- EP240919a is likely a GRB event
- EP240919a: EP-WXT detection of a fast X-ray transient
- EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
- EP240918a: EP observation update
- GRB 240916A: GRBAlpha detection
- GRB 240914B: GRBAlpha detection
- EP240918a: an X-ray transient detected by Einstein Probe
- GRB 240916A: NOT optical observation
- GRB 240821A: radio observation with the VLA