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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
19123 results found.
- EP241021a: further SAO RAS optical observations
- EP 241026b: LBT optical observations
- EP241021a: e-MERLIN radio observation
- GRB 241026A: Enhanced Swift-XRT position
- EP241026b: EP detection of a fast X-ray transient
- GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
- GRB 241026A: SAO RAS observations of possible optical afterglow
- GRB 241026A: Swift detection of a burst
- GRB241025A: 1.3m DFOT optical afterglow detection
- EP241021a: optical follow-up observations with Xinglong Observatory
- GRB 241025A: GROWTH-India Telescope optical observations
- GRB 241025A: COLIBRÍ Detection of the Afterglow
- GRB 241025C: Fermi GBM Detection
- IPN triangulation of GRB 241022A (short/hard)
- LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
- GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
- GRB 241025A : SVOM/VT optical afterglow observations
- EP241021a: Liverpool Telescope optical follow-up observations
- GRB 241025A: Enhanced Swift-XRT position
- GRB 241025A: DDOTI Afterglow detection
- GRB 241025A: TRT optical afterglow observation
- GRB 241025A: Swift detection of a burst with an optical counterpart
- EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
- GRB 241001A: ATCA radio observations
- GRB 241010A: VIRT Optical Upper Limit
- EP241021a: SAO RAS optical observations
- EP241021a: KAIT optical observations
- EP241021a: EP-FXT follow-up observation update
- EP241021a: 1.3m DFOT Optical observations
- EP241021a: Optical upper limits with Kinder observations
- EP241021a: TRT optical observations
- GRB 241018A: SVOM/C-GFT optical observations
- EP241021a: NOT likely optical counterpart
- GRB241017A: 1.3m DFOT optical upper limit
- GRB 241018A: 1.3m DFOT Optical upper limit
- EP241021a: GOTO optical upper limits
- EP241021a: EP detection of a fast X-ray transient
- Konus-Wind detection of GRB 241018A
- GRB 241018A: SVOM/GRM observation
- GRB 241018A/sb24101802: Mephisto optical upper limit
- GRB 241017A/sb24101702: Mephisto optical upper limit
- GRB 241018A: Mondy optical upper limit
- GRB 241018A: SVOM/VT further analysis and counterpart confirmed
- GRB 241018A: GROWTH-India telescope optical upper limit
- GRB241018A: XingLong Optical Upper Limit
- GRB 241018A: Swift-XRT observations
- GRB 241018A: REM optical/NIR upper limits
- GRB 241018A: NOT optical observations
- GRB 241018A: SVOM/VT follow-up and optical candidate
- GRB 241018A: LCO/0.4m optical upper limits
- GRB 241006A: VIRT Optical Upper Limit
- GRB 240727A: VIRT Optical Upper Limit
- GRB 241018A: X-ray afterglow candidate observed by MXT
- GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
- GRB 241017A: GROWTH-India Telescope optical upper limit
- GRB241017A: TOO Observations by SVOM/MXT
- GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
- GRB 241017A: J-band upper limit from WINTER
- GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
- GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
- GRB 240916A: radio detection with the VLA
- GRB241013A: REM observations
- GRB 241009A: LCO optical upper limits
- LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
- GRB 241009A: GRANDMA optical upper limits
- GRB 241009A: Swift-XRT afterglow detection
- GRB 241010A: JinShan optical observations and potential host galaxy
- GRB 241010A: J-band observations with WINTER
- GRB 241010A: Enhanced Swift-XRT position
- GRB 241010A: LCO optical observations
- GRB 241010A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
- GRB 241002B: Swift-XRT afterglow detection
- LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
- GRB 241002A: NOT optical upper limits
- LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
- IceCube-241006A: No candidates from the Zwicky Transient Facility
- GRB 241006A: GRANDMA optical upper limits
- GRB 241002B: PRIME near-infrared detection in 3rd epoch
- Fermi-LAT Gamma-ray Observations of NuEm-240926A
- GRB 240910A: LBT optical observations
- EP trigger ID 01709065118: KAIT confirmation of the stellar flare
- GRB 241006A: PRIME near-infrared upper limits
- GRB 241006A: Swift/UVOT Upper Limits
- LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
- GRB 241001A: Swift-XRT afterglow detection
- GRB 241006A: Enhanced Swift-XRT position
- GRB 241006A: Swift detection of a burst
- GRB 240930B: SVOM/C-GFT optical upper limit
- LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
- EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
- GRB 241001A : ECLAIRs spectral analysis and XRF classification
- GRB 241002B: PRIME near-infrared detection in 2nd epoch
- GRB 241002C: SVOM/C-GFT optical upper limit
- GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
- Konus-Wind detection of GRB 240926A
- GRB 241002B: PRIME near-infrared detection
- LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
- IPN triangulation of GRB 240930B / EP 240930a
- GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc