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"
3035 results found.
- GRB 240730A: Swift-XRT refined Analysis
- GRB 240715A: Swift-XRT afterglow detection
- GRB 240727B: Swift-XRT observations
- GRB 240727A: Swift-XRT refined Analysis
- IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
- GRB 240715A: Swift/UVOT observations of the XRT sources.
- GRB 240715A: Swift-XRT observations
- GRB240713A: Swift/UVOT Upper LImits
- GRB 240713A: Swift-XRT observations
- GRB 240712A: Swift-XRT refined Analysis
- The EP-WXT source triggered on July 14th is likely a flaring star
- GRB240713A: X-ray follow-up observation with EP-FXT
- EP240703c: EP-WXT detection of an X-ray transient
- EP240618a: Swift/XRT upper limit
- EP240617a: tentative Swift/XRT detection of the afterglow
- GRB 240619A: Swift-XRT probable afterglow detection
- LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
- GRB 240615A: Swift-XRT observations
- GRB 240606B: Swift-XRT afterglow detection
- Swift Trigger 1235109: a possible GRB 240606A
- Swift Trigger 1232755: likely consistent with noise and not astrophysical
- Swift Trigger 1232465: consistent with noise
- The EP-WXT source triggered on June 1st is likely a flaring star
- GRB 240529A: Swift-XRT refined Analysis
- GRB 240527B: Swift-XRT afterglow detection
- GRB 240523A: Swift-XRT refined Analysis
- EP240518a: possibly identified with a flare star by EP-FXT
- GRB 240516A: Swift-XRT refined Analysis
- GRB 240513A: Swift-XRT observations
- GRB 240511A: Swift-XRT refined Analysis
- LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
- LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
- XMM-Newton observation of EP240426a
- LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
- LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
- LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LXT240402A/GRB240402B: Chandra X-ray detection
- GRB 240415B: Swift-XRT observations
- GRB 240415A: Swift-XRT refined Analysis
- GRB 240421B: Swift-XRT refined Analysis
- EP240420a: detection of fading X-ray emission with refined position by EP-FXT
- GRB240418A - Candidate afterglow from NIRES
- GRB 240419B: Swift-XRT refined Analysis
- GRB 240419A: Swift-XRT refined Analysis
- GRB 240418A: Swift-XRT refined Analysis
- EP240414a: EP-FXT follow-up observation
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Swift-XRT refined Analysis
- EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
- GRB 240411B: Swift-XRT refined Analysis
- Fermi GRB 240407A: Global MASTER-Net observations report
- LXT 240402A: EP-FXT detection of the X-ray afterglow
- X-ray transient EP 240315a: Second epoch Chandra observations
- X-ray transient EP 240315a: Chandra observations
- GRB 240225B: Swift-XRT afterglow detection
- GRB 240215A: Swift-XRT afterglow detection
- GRB 240225B: Swift-XRT observations
- Transient EPW20240219aa: Kp-band imaging observations with NIRES
- GRB 240222A: Swift-XRT refined Analysis
- GRB 240218A: LBT H-band detection
- Konus-Wind detection of GRB 240218A
- GRB 240218A: Swift-XRT refined Analysis
- Fermi GRB 240216A: Global MASTER-Net observations report
- GRB 240128A: Further Swift-XRT observations
- GRB240204A: Swift/UVOT Upper Limits
- GRB 240128A: Swift-XRT observations
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240123A: Swift-XRT refined Analysis
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240118A: Swift-XRT afterglow detection
- GRB 240112C: Swift-XRT refined Analysis
- GRB 231220A: Swift-UVOT upper limit
- GRB 240101B: Swift-XRT refined Analysis
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240101B: Swift/UVOT Upper Limits
- GRB 240101A: Swift-XRT refined Analysis
- GRB 231230A: Swift-XRT refined Analysis
- Fermi trigger No 725592555: Global MASTER-Net observations report
- GRB 231222B: Swift-XRT afterglow detection
- GRB 231220A: Swift-XRT follow-up observations
- GRB 231216A: Swift-XRT refined Analysis
- GRB 231215A: Swift-XRT refined Analysis
- GRB 231214A: Swift-XRT refined Analysis
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231205B: Swift-XRT refined Analysis
- GRB 231129C: Swift-XRT afterglow detection
- GRB 231129B: Swift-XRT observations
- GRB 231129C: Swift-XRT observations
- GRB 231129A: Swift-XRT refined Analysis
- GRB 231123C: Insight-HXMT/HE detection
- GRB 231115A: XMM-Newton observation
- GRB 231117A: GTC Near-Infrared Observations
- GRB 231117A: Swift-XRT refined Analysis
- GRB 231118A: Swift-XRT refined Analysis
- GRB 231115A: NuSTAR Follow-Up Observations
- GRB 231115A: Swift-XRT and Swift-UVOT observations
- GRB 231115A: archival Chandra X-ray observations
- GRB 231110A: Swift-UVOT Upper Limits
- GRB 231111A: Swift-XRT refined Analysis