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"15247 results found.
- GRB020321: a faint BeppoSAX detection
- GRB020305: NIR observations
- GRB 020317 : KISO Optical Observations
- GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
- GRB 011121: Third HST Epoch
- GRB020305: Properties of the Candidate Optical Afterglow
- GRB011130 (XRF011130) Second Epoch Chandra Observations
- GRB020305: Subaru Optical Observations
- XRF/GRB 011030: Detection of the Probable Host Galaxy
- GRB020305, optical observations
- GRB020305 (=H1939): Localization of a GRB by HETE
- GRB 010921: HST Observations
- IPN detection and localization of Cygnus X-1 flares
- IPN Upper Limits to a GRB Associated With SN2002ap
- GRB020124 BVRI field photometry
- GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
- SN2002ap (SN/GRB?) Echelle spectra
- SN2002ap (SN/GRB?) optical spectrographic observations
- SN 2002ap (SN/GRB?)
- SN 2002ap in M74
- Type Ib/c SN2002ap (SN/GRB?)
- GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
- VLT observations of GRB 020124: The fading optical/near-infrared afterglow
- GRB 020124: Optical observations
- GRB 020124 Optical Observations
- IPN triangulation of GRB020124 (HETE 1896)
- GRB020124(=H1896): Localization of a Long GRB by HETE
- GRB optical counterpart candidate in GCN 1217 is M dwarf
- GRB011212, Optical Observations
- GRB011211: BeppoSAX/GRBM data
- Optical polarization observations for GRB011211
- GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
- GRB 011211: TNG Spectroscopic Observations
- GRB011211, BVRI field photometry
- GRB 011211: BVRi-band photometry
- GRB 011211 Optical Observations: Likely Afterglow
- GRB011130 (=XRF011130): Further analysis of Chandra Target of
- GRB011130 (XRF011130) Chandra Observations
- GRB 011130: Magellan spectroscopy
- Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
- GRB 011130, K band observations
- GRB011130 (=XRF011130): Second Revised Localization by HETE
- GRB 011130 I-band Observation
- GRB011130 (XRF011130) SDSS PT i-band observations
- GRB011130 (=XRF011130): Revised Localization of an X-ray
- GRB 011121
- GRB 011121: J-band observations
- GRB010921 - Milagro GeV/TeV Observations
- Correction: GCN1157 (GRB 011121)
- GRB011121: UBRI Observations
- GRB 011121: Radio Observations
- GRB 011121 J-Band Astrometry
- GRB011121: possible redshift, continued decay
- GRB011121: fading behavior
- GRB 011030: TNG K-band observation
- XRF011030: J and K band observations
- XRF011030: Chandra Observations
- GRB 011030: K-band observations
- GRB011030: Z-band observations
- GRB 011030 R band observations
- GRB 011030 I-band Observation
- The X-ray Flash 011030 ('GRB 011030')
- Non-triggered burst 011030 ("GRB 011030")
- The Radio Afterglow from the X-ray Rich GRB 011030
- GRB 970828: HST Observations 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
- GRB 011030 K-band Observations
- GRB010921, optical observations
- GRB010921, optical observation at early time
- GRB 010921, I-band observations
- GRB010921: Spectroscopy of the Host Galaxy
- Optical Observations of the field of HETE trigger #1793/GRB 011012?
- 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
- H1761: A Bright GRB Detected by HETE
- HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
- HETE Trigger #1760 (GRB 010920B?): a new optical source
- HETE Trigger #1759 (GRB 010920?) optical observations
- GRB001109, Host Galaxy Spectroscopic Observations
- GRB 010222: HST observations -- host galaxy and late-time decay
- BeppoSAX/GRBM detection of GRB 010801
- Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
- BeppoSAX/GRBM detection of GRB010728
- GRB 010222 - WHT BVRI images
- SGR1900+14 burst seen by HETE: BeppoSAX data
- GRB 010629 Optical Observations
- GRB010629: Optical Observations
- SGR1900+14: High Fluence Burst Localized by HETE
- GRB010629, optical observations
- GRB010629: A Burst Localized by HETE
- SGR1900+14: Second Burst Localized by HETE
- SGR1900+14: A Burst Localized by HETE
- SGR1806-20: A Second, Intense Burst Localized by HETE
- SGR1806-20: Localization by HETE
- GRB010518: a faint BeppoSAX detection
- X-ray precursors to the large flare from SGR 1900+14