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.
Advanced Search Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
- GRB010214 refined WFC position
- BeppoSAX ALERT: GRB010214
- IPN Status Report
- HETE Status
- GRB010126 opt. obs.
- IPN/RXTE TRIANGULATION OF GRB010126
- GRB010126: CONCAM crude optical limits during GRB
- GRB010126, TNG R-band observations
- GRB010126 Optical Observations
- GRB010126 optical observations
- GRB010126: Optical observations
- IPN TRIANGULATION OF GRB010126
- IPN/RXTE TRIANGULATION OF GRB010126
- GRB 010119, optical observations
- GRB010119: Optical observations
- Optical Observations of GRB 001018 at Keck
- GRB010119, Radio observations
- IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
- Optical observations of GRB 001018 with JCAM
- IPN TRIANGULATION OF GRB010115
- IPN TRIANGULATION OF GRB010109
- IPN TRIANGULATION OF GRB010109
- GRB010103, optical observations
- IPN triangulation of GRB010104
- IPN triangulation of GRB010103
- GRB 001204: Ks observations
- H band observation of GRB 001212
- GRB & BeppoSAX: ground operations restored back to 24 hrs a day
- IPN triangulation of GRB001219
- GRB 001212 Optical Observation
- GRB 001212 Optical Observation
- GRB 001212 optical observation
- GRB 001212 possible OA in 2MASS
- GRB 001212 possible OA
- IPN triangulation of GRB001212
- GRB001204: Optical observations
- Confirmation of IPN position for GRB001204
- GRB001204, Radio observations
- IPN triangulation of GRB001204 (short/hard)
- GRB 001105, further optical observations
- GRB001120: Gunn-i observations
- GRB001120: Optical observations
- GRB001109, optical observations
- GRB001120, optical observations
- WSRT 4.8 GHz observations of GRB001109
- IPN triangulation of GRB001120
- Optical/NIR observations of GRB001109
- GRB 001109: deep JHK upper limits
- GRB 001109 X-ray afterglow with BeppoSAX
- CORRECTION to XMM-Newton observation of GRB001025
- GRB001109: Optical observations
- GRB001109: BeppoSAX/NFI Observations
- GRB001109, R-band optical observations
- GRB001109, Radio observations
- GRB001109: BeppoSAX refined WFC position
- BeppoSAX ALERT: GRB001109
- GRB001105 BVRI field photometry correction
- GRB001105, BVRI field photometry
- GRB 001105, R-band observation
- IPN TRIANGULATION OF GRB001105
- GRB 001025B, Optical obervations
- GRB 991208: HST Imaging of the Host Galaxy
- GRB000926: R-image of the host galaxy
- GRB 001025B, I-band observations
- XMM-Newton observation of GRB001025
- GRB001025B, Radio observations
- GRB 001025 Optical Observations
- GRB 001025A, optical observation
- IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
- CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
- IPN triangulation of GRB001025
- GRB001007: Optical observations
- ASM Localization of GRB 001025
- GRB001007, Radio observations
- IPN TRIANGULATION OF GRB001020
- GRB001019, Optical Observations
- GRB 001018, Possible Radio Afterglow
- GRB001018, Gamma Ray Observations
- IPN TRIANGULATION OF GRB001019
- CORRECTION TO PEAK FLUX OF GRB001018
- IPN TRIANGULATION OF GRB001018
- IPN TRIANGULATION OF GRB 001017
- GRB 000926: Improved Absorber Redshift
- V,R,I band observations of GRB000926
- The Likely Optical/Infrared Afterglow of GRB 001011
- HETE positions added to GCN
- GRB001011 BeppoSAX/WFC refined position
- BeppoSAX ALERT: GRB001011
- GRB 001007, BVR-band observations
- GRB000926 - Amateur Optical Observations
- GRB001007: Optical observations
- CONCAM null result on GRB001005
- IPN triangulation of GRB001007
- GRB 000926 : the host galaxy
- HETE-2 Launches Successfully
- IPN triangulation of GRB001005
- HETE-2 48 hour Launch Delay
- GRB 000926 Chandra Observation
- IPN triangulation of GRB 001004
- Public availability of BeppoSAX data of GRB000926