GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"26672 results found.
- GRB 250805A: Swift-XRT refined Analysis
- GRB 250804B: Swift-XRT observations
- GRB 250805A: Enhanced Swift-XRT position
- GRB 250805A: TRT optical upper limits
- GRB 250805A: Swift-XRT observations
- GRB 250804B: SVOM/GRM observation of a short burst
- EP250802a: additional Liverpool Telescope upper limits
- EP250730a: SVOM/VT optical upper limit
- EP250802a: Liverpool Telescope optical upper limits
- EP250802a: GROWTH-India Telescope optical upper limit
- EP250802a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709198251 is likely a flaring star
- LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
- The EP-WXT trigger 01709198202 is likely a flaring star
- LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
- LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
- LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
- EP250711a: CrAO and Assy optical observations
- LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
- EP250730a: COLIBRÍ optical upper limit
- GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
- EP250730a: Einstein Probe detection of an X-ray transient
- LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
- LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
- GRB 250727A: EP-FXT follow-up observation
- GRB 250725A: PRIME near-infrared observations
- LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
- LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
- GRB 250728A: Swift-XRT observations
- GRB 250727A: SVOM/ECLAIRs refined analysis
- EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
- GRB 250728A: COLIBRÍ optical upper limit
- GRB 250728A: Fermi GBM Observation
- GRB 250727A: AST3-2 Upper limit
- GRB 250727A: EP-FXT counterpart detection
- GRB250727A: SVOM/VT optical upper limit
- GRB 250727A: Swift-XRT observations
- LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
- GRB 250727A: SVOM detection of a burst
- The EP-WXT trigger 01709195487 is likely a flaring star
- Swift detection of the Soft Gamma Repeater PSR J1647-4552
- LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
- GRB 250725A: Swift-XRT refined Analysis
- GRB 250725A: Fermi GBM Observation
- GRB 250725A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 250725A
- GRB 250725A: SVOM/GRM observation
- GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
- GRB 250725A: Swift/UVOT Upper Limits
- GRB 250725A: SVOM/VT optical candidate
- GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
- LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
- GRB 250725A: Enhanced Swift-XRT position
- GRB 250725A: Swift detection of a burst
- EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
- SVOM J195836+32283 is not a real source
- EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
- SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
- GRB 250721A: Fermi GBM Observation
- SVOM J195836+32283/sb25072103: NIR observations with WINTER
- GRB 250721A: Swift-XRT observations
- GRB 250713A : SVOM/ECLAIRs refined analysis
- GRB 250717B: SVOM/GRM observation
- The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
- GRB 250717B: COLIBRÍ optical upper limit
- LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
- Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
- GRB 270713A: Kitab and AbAO Optical Observations
- GRB 250717B: Fermi GBM Observation
- GRB 250716A: Swift-XRT afterglow detection
- GRB 250716A: Fermi GBM Observation
- GRB 250714A: SVOM/GRM observation
- EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
- GRB 250713A: Mephisto optical upper limits
- GRB 250713A: SVOM/VT optical upper limit
- GRB 250713A: NOT optical upper limits
- GRB 250713A: OHP/T193 upper limit
- GRB 250713A: SVOM/C-GFT upper limit
- GRB 250706B/C: 7DT Follow-up Observations
- GRB 250713A: Swift-XRT observations
- GRB 250713A: EP-FXT counterpart detection
- EP250711a: COLIBRÍ continuous optical observations
- GRB 250706A: Swift-BAT refined analysis
- GRB 250713A: JinShan optical upper limits
- GRB 250713A: SVOM detection of a long burst
- GRB 250711A: DDOTI Optical Upper Limit
- LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
- EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
- GRB 250711A: SVOM/GRM observation
- EP250711a: NOT optical counterpart candidate
- EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
- EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
- EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
- GRB 250704A: GRANDMA observations