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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"23633 results found.
- GRB020124 optical observations with RIBOTS/RIMOTS
- GRB 020321: Candidate X-ray Counterparts
- ASM GRB candidate 020406 refined error box
- GRB 020331: Candidate Optical Afterglow
- Short RXTE/ASM transient 020406; may be a GRB
- Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
- IPN localization of GRB020405
- GRB 020331: NIR Observations
- GRB020331 NIR observation at KPNO (re-submission)
- GRB02033 NIR observation at KPNO
- GRB 020331, NIR observations
- GRB020331(=H1963): The "Easter" Burst Detected by HETE
- GRB 020322: BeppoSAX observations of the X-ray afterglow
- SN 2002ap - peak brightness date (SN/GRB?)
- GRB 020322 optical observations
- GRB 011121: Fourth Epoch of HST Imaging
- GRB020321: a faint BeppoSAX detection
- GRB 020317 : KISO Optical Observations
- GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
- GRB 020305: Optical Observations
- GRB020317, optical observations
- GRB 011121: Third HST Epoch
- GRB 011121: HST Observations reveal an intermediate-time multicolor
- GRB011121, possible supernova association
- XRF/GRB 011030: Detection of the Probable Host Galaxy
- GRB020305, optical observations
- IPN triangulation of GRB020305 (HETE 1939)
- GRB020305 (=H1939): Localization of a GRB by HETE
- HST Imaging of the afterglow and host of GRB 011121
- IPN detection and localization of Cygnus X-1 flares
- RXTE Observations of SGR 1900+14
- IPN detection of further SGR1900+14 activity
- SGR1900+14 activity
- IPN/HETE Detection of Bursts from SGR1900+14
- IPN Upper Limits to a GRB Associated With SN2002ap
- GRB020127: Palomar and VLA Observations of Possible Counterparts
- GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
- SN2002ap (SN/GRB?) Echelle spectra
- GRB020127 Optical Observations
- SN2002ap (SN/GRB?) UBVRI Field Photometry
- GRB020127: Chandra Observations and Prospective Counterparts
- GRB020124, optical observations
- IPN detection of further activity from SGR1806-20
- GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
- GRB020124: Optical observations
- IPN observations of SGR1806-20
- GRB 020124: Optical afterglow
- GRB020124(=H1896): Localization of a Long GRB by HETE
- GRB 011211, spectrum and optical photometry
- GRB 011211: TNG Spectroscopic Observations
- GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
- GRB011130, optical observations
- GRB011130 (=XRF011130): Second Revised Localization by HETE
- GRB011130 (XRF011130) optical observations
- GRB011130 (=XRF011130): Revised Localization of an X-ray
- GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
- GRB 011121: J-band observations
- GRB011121
- GRB011030: Z-band observations
- GRB 010921: HST Detection of the Afterglow and Host Galaxy
- GRB 970828: HST Observations of the Host Galaxy
- GRB 000131: HST Detection of the Host Galaxy
- GRB 970828: HST Observations of the Host Galaxy
- GRB010921, optical observation
- Optical observation of SGR 1806-20 at the 6-m SAO telescope
- GRB011019: Subaru Optical Observations
- GRB010921, optical observation at early time
- GRB 010921, I-band observations
- GRB011019: A Faint, X-ray Rich GRB localized by HETE
- GRB010921: Spectroscopy of the Host Galaxy
- GRB010923 as seen by BeppoSAX GRBM
- GRB010928(=H1770): Localization of a Long GRB by HETE
- GRB010923(=H1764): A Short Duration GRB Detected by HETE
- GRB010921, negative optical observations
- GRB010921 Optical Observations
- H1761: A Bright GRB Detected by HETE
- HETE Trigger #1760 (GRB 010920B?): a new optical source
- HETE Trigger #1759 (GRB 010920?) optical observations
- GRB 010222: HST observations -- host galaxy and late-time decay
- Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
- SGR1900+14 burst seen by HETE: BeppoSAX data
- SGR1900+14: High Fluence Burst Localized by HETE
- GRB010629: A Burst Localized by HETE
- SGR1900+14: Second Burst Localized by HETE
- SGR1900+14: A Burst Localized by HETE
- Possible burst from SGR1806-20
- IPN detection of SGR1900+14
- SGR1806-20: A Second, Intense Burst Localized by HETE
- SGR1806-20: Localization by HETE
- HETE Fully-Automated GCN Notices
- GRB000301C: Late-time HST/STIS observation
- GRB010518: a faint BeppoSAX detection
- GRB000418: HST/STIS Second-epoch Observations
- X-ray precursors to the large flare from SGR 1900+14
- GRB010427, Gamma Ray Observations
- SGR 1900+14 : RXTE observations
- Chandra Observations of SGR 1900+14
- Possible precursor to the SGR1900+14 giant burst
- SGR1900+14, I-band observations
- IPN Triangulation of the Giant Flare from SGR1900+14