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').
19122 results found.
- EP241104a: EP detection of GRB 241104A X-ray emission
- GRB 241010A: host galaxy redshift z = 0.977
- EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
- GRB 240821A: further radio observations with the VLA
- GRB 241030A: GRBAlpha detection
- EP241103a: GIT optical upper limit
- EP241021a: OHP/T193 further optical observations
- LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
- EP241103a: Swift XRT detection and improved X-ray position
- EP241021a: continued SOAR observations
- EP241101a: Optical upper limits with Kinder observations
- EP241101a: OHP/T193 optical observations
- LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
- GRB 241030A: Swift-UVOT observations of the optical prompt flare
- EP241103A: LCO optical observations
- EP241103a: an X-ray transient detected by Einstein Probe
- GRB 241029A: GRBAlpha detection
- EP241101a: BOOTES-7 optical upper limit
- S241102cy: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
- Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
- GRB241030A: OHP/T193 optical observations
- GRB 241101A: FRAM-ORM optical limit
- LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
- GRB 241030A/EP241030a: TNOT observations of the optical counterpart
- EP241021a: Upper limit from Konus-Wind observations
- GRB 241030A: further SAO RAS optical observations
- GRB 241030A: Optical Observations via Virtual Telescope Project
- EP241021a: Liverpool Telescope optical follow-up observations
- GRB 241026A: SAO RAS optical observations
- GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
- EP241021a: OHP/T193 optical observations
- GRB 241030A: Palomar 1-m telescope COSMOS optical observations
- GRB 241030B: Montarrenti Observatory optical upper limit
- EP241026b: Liverpool Telescope optical follow-up
- GRB 241030A: SAO RAS optical observations
- EP241021a: AMI-LA radio detection
- GRB 241030B : GIT optical upper limits
- GRB 241030B: LCOGT Optical Upper Limits
- GRB 241030A: Swift-BAT refined analysis
- GRB 241029A: COLIBRI Detection of the Optical Counterpart
- GRB 241030B: Swift/UVOT Detection
- GRB 241029A: LCO optical detection
- GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
- GRB 241030B : MITSuME Akeno optical upper limits
- GRB 241030A: COLIBRI Continuing Detection of the Afterglow
- GRB 241030B: SVOM/VT optical afterglow observations
- GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
- EP241030a: EP detection of GRB 241030A X-ray Afterglow
- GRB 241030B: BTA observations
- GRB 241029A: SVOM/VT optical afterglow observations
- GRB 241030B: Enhanced Swift-XRT position
- GRB241030B: GRANDMA/TAROT Upper Limit
- GRB 241030B: SAO RAS optical observations
- GRB 241030B: AKO Optical Afterglow Detection
- GRB 241030B: Nanshan/HMT optical afterglow detection
- Konus-Wind detection of GRB 241030A
- GRB 241030B: Swift detection of a burst
- GRB 240912A: radio detection with the VLA
- GRB 241030A: AKO Optical Afterglow Detection
- GRB 241030A: Swift/UVOT Detection
- GRB 241030A: SVOM/C-GFT optical observations
- GRB 241026A: LBT optical observations
- EP241021a: Optical rebrightening observations with Mephisto
- GRB 241030A: Multiband optical detection with Mephisto
- GRB 241030A: SVOM/VT optical afterglow observations
- GRB 241030A : MITSuME Akeno optical afterglow detection
- GRB 241030A: Enhanced Swift-XRT position
- GRB 241029A: GROWTH-India Telescope optical follow up
- GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
- GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
- GRB 241030A: Swift detection of a burst with a bright optical counterpart
- GRB 241029A: SAO RAS optical observations
- GRB 241026A: SAO RAS optical observations
- EP241021a: SAO RAS observations of rebrightening
- GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
- MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
- GRB 241026A: Swift/UVOT Upper Limits
- GRB 241029A: AKO Optical Afterglow Detection
- EP241021a: continued SOAR observations confirm optical rebrightening
- GRB 241029A: Xinglong-2.16m optical afterglow confirmation
- GRB 241029A: Mephisto observations
- EP 241026b: LBT possible optical counterpart (brightening source)
- GRB 241029A: TRT optical afterglow candidate detection
- GRB 241026A: the 100th GRB detected by GRBAlpha
- GRB 241026A: TNOT optical counterpart detection
- Konus-Wind detection of GRB 241025A
- GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
- GRB 241025A: further SAO RAS optical observations
- GRB 241026A: BTA and Zeiss-1000 optical observations
- GRB 241026A: SVOM/GRM observation
- EP241026B: GROWTH-India Telescope optical upper limit
- GRB 241025A: Swift/UVOT Detection
- GRB 241026A: GROWTH-India Telescope optical observations
- GRB 241026A: J-band observations with WINTER
- GRB 241025A: SAO RAS optical observations
- GRB 241026A: Las Cumbres optical detection
- GRB 241025A: Mondy optical observations
- EP241021a: SOAR observations of the optical counterpart
- EP241021a: further SAO RAS optical observations