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"
- IPN triangulation of GRB030215C (annulus)
- IPN triangulation of GRB030217 (annulus)
- IPN triangulation of GRB030216 (annulus)
- IPN triangulation of GRB030215A and GRB030215B (annuli)
- GRB030115, WSRT radio observations - correction to GCN 1864
- GRB 030131: marginal optical detection
- GCN/INTEGRAL Mistake Fixed
- GRB030115, WSRT radio observations
- IPN triangulation of GRB030206 (annulus)
- IPN triangulation of GRB030208 (annulus)
- GRB 030204: Optical Observations
- GRB030204 field photometry
- GRB020819: Kiso R and I band observations
- GRB 030204: Correction to GCN 1856
- GRB030131: Candidate Optical Afterglow
- GRB 030115: Optical Observations
- GRB 030204, optical observations
- IPN triangulation of GRB030204 (small error box)
- IPN triangulation of GRB030202 (annulus)
- GRB 030131, optical observations
- GRB030131: Kiso optical limit for corrected position
- GRB030131: Optical limits for corrected position
- GRB 030131: afterglow candidate
- GRB 030115, late-time optical observations
- GRB030131: corrected INTEGRAL position
- Type Ic SN2003L (SN/GRB?), optical spectrum
- GRB030131: Kiso Observations
- GRB 020819: Host galaxy at Radio Position
- IPN triangulation of GRB030131 - CORRECTION
- GRB 020819: afterglow candidate
- IPN triangulation of GRB030131
- GRB030131: Optical limit
- GRB 030131 optical observations
- GRB030131: refined position
- GRB 030131 optical observations
- A long GRB detected by INTEGRAL
- GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
- Type Ic SN2003L (SN/GRB?) Radio Observations
- IPN triangulation of GRB030127 (annulus)
- GRB030115 submm upper limit
- IPN triangulation of GRB030119 (two large error boxes)
- GRB 030115: Further IR observations with IRSF/SIRIUS
- IPN triangulation of GRB030117 (two large error boxes)
- Publicizing GRB Discoveries - A Message from NASA HQ
- GRB 030115: Radio detection of IR candidate
- GRB 030115, simultaneous observations by BOOTES-1
- GRB 030115: IR observations with IRSF/SIRIUS
- IPN triangulation of GRB030115C (large error box)
- GRB030115: R-band counterpart of IR candidate
- GRB030115, afterglow candidate
- GRB 021211: R-band observations at late-time
- GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
- IPN triangulation of GRB030115B (small error box)
- GRB 030115 : Possible IR counterpart
- GRB 030115: Radio Observations
- GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
- Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
- IPN triangulation of GRB030115B (annulus)
- ANNOUNCEMENT ON INTEGRAL GRB ALERTS
- Distribution of INTEGRAL SPI-ACS triggers
- GRB030115: R-band observations at Asiago
- GRB030115: TAROT optical observations
- GRB 021211: VLT spectrum
- GRB 030115: APO Optical Observations
- GRB 030115, no optical candidate
- GRB 030115, optical observations
- GRB 030115, optical candidate
- Possible GRB030113 seen by SPI ACS
- Probable GRB030112B seen by SPI ACS
- Probable GRB030112 seen by SPI ACS
- Information about where HETE will be pointing
- Possible GRB030111 seen by SPI ACS
- Possible GRB030110b seen by SPI ACS
- Possible GRB 030110 seen by SPI ACS
- IPN triangulation of GRB030109 (annulus)
- IPN triangulation of GRB030105 (large error box)
- IPN triangulation of GRB030102B (refined localization - portion of annulus)
- Possible GRB 20030109 seen by SPI ACS
- IPN triangulation of GRB030102A - correction to peak flux
- IPN triangulation of GRB030102B (portion of annulus)
- IPN triangulation of GRB030102A (large error box)
- Coronas-F -Wind triangulation of GRB030102
- Possible GRB20030107 seen by SPI-ACS
- Possible GRB 20030105 seen by SPI ACS
- IPN triangulation of GRB030102 (annulus)
- GRB on 20030102 seen by SPI-ACS
- VLT spectroscopy of the probable host of GRB 021211
- GRB on 20030101 seen by SPI-ACS
- IPN triangulation of GRB030101 (two large error boxes)
- GRB021226
- GRB 021211: Probable Host and Underlying Supernova
- GRB 021226 registration by Helicon/Coronas-F
- Probable GRB in INTEGRAL SPI-ACS
- IPN triangulation of GRB021223 (two large error boxes)
- GRB021211, radio observations
- GRB 021112: Evidence for Another Dark Optical Afterglow
- GRB 021219: OSN optical observations
- GRB021219: Radio Observations
- GRB021219, optical observations
- IPN triangulation of GRB021219 - CORRECTION