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"26299 results found.
- GRB020819: Kiso R and I band observations
- GRB030131: Candidate Optical Afterglow
- IPN triangulation of GRB030204 (small error box)
- IPN triangulation of GRB030202 (annulus)
- GRB 030131, optical observations
- GRB030131: Optical limits for corrected position
- GRB 030115, late-time optical observations
- GRB030131: corrected INTEGRAL position
- GRB030131: Kiso Observations
- GRB 020819: Host galaxy at Radio Position
- IPN triangulation of GRB030131
- GRB030131: Optical limit
- GRB030131: refined position
- A long GRB detected by INTEGRAL
- IPN triangulation of GRB030127 (annulus)
- 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 (=H2533): A Long GRB Localized by the HETE WXM and SXC
- IPN triangulation of GRB030115B (annulus)
- ANNOUNCEMENT ON INTEGRAL GRB ALERTS
- GRB030115: TAROT optical observations
- GRB 021211: VLT spectrum
- 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)
- Possible GRB 20030109 seen by SPI ACS
- IPN triangulation of GRB030102B (portion of annulus)
- IPN triangulation of GRB030102A (large error box)
- 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
- IPN triangulation of GRB021223 (two large error boxes)
- GRB 021112: Evidence for Another Dark Optical Afterglow
- GRB 021219: OSN optical observations
- IPN triangulation of GRB021219
- GRB021219, optical observation by MASTER
- VLT spectra of GRB 021211 revisited
- GRB021219: a long GRB localized by INTEGRAL
- GRB021211: APO optical observations
- IPN detection of continued activity from SGR1806-20
- IPN triangulation of GRB021215 (large error box)
- IPN triangulation of GRB021214 (annulus)
- XRF 020903 : HST observations
- GRB 021211, optical observations
- GRB021211: Measurement of Early Time Afterglow
- IPN triangulation of GRB021211B (two large error boxes)
- GRB 021211: early break in light curve
- GRB021211: Optical observations in CrAO
- GRB 021211: Optical Observations
- GRB 021201, optical observations
- GRB021211: Optical observations
- GRB 021211 Milagro GeV/TeV Observations
- GRB021211 - Upper limits from recent and historical observations
- GRB021211, OT at 108 s
- GRB021211 (HETE2493), OT at 143 sec
- GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
- GRB 021125: Radio Observations
- IPN triangulation of GRB021206 (exceptionally bright; annulus only)
- IPN detection of renewed activity from SGR1806-20
- IPN triangulation of GRB021205 (large error box)
- GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
- GRB 021201, Radio Observations
- IPN triangulation of GRB021201 (short/hard burst, small error box)
- IPN triangulation of GRB021115 (annulus)
- IPN triangulation of GRB021125B (two large error boxes)
- IPN triangulation of GRB021119 (large error box)
- IPN triangulation of GRB021125B (annulus)
- Improved IPN error box for GRB021125
- IPN triangulation of GRB021125 (INTEGRAL BURST)
- GRB021125 : A long GRB localized by INTEGRAL
- IPN detection of possible reactivation of SGR1900+14
- GRB021113, SPI ACS observation
- IPN triangulation of GRB021119 (annulus)
- GRB 021112: Afterglow or Variable Star?
- GRB 021112, Radio Observations
- GRB 021112: Variable Source in R-band search
- GRB021112: Optical Observations
- GRB021113: Kiso Observations
- IPN triangulation of GRB021113 (=H2449; annulus)