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"28061 results found.
- GRB 040511, very fast decay?
- GRB 030324: Detection and Color of Host Galaxy
- GRB 040511: NIR observations with REM
- GRB040511: Candidate optical/NIR afterglow
- GRB 040511: ROTSE-III Rapid Optical Upper Limits
- GRB 040511: Second Epoch Optical Observations
- GRB 040511: Optical observations
- GRB 040511: Optical Observations
- GRB040511: Optical Observations
- GRB040511: Optical Observations
- Type Ic SN2001em (off-axis GRB jet?), optical spectrum
- GRB 040423 (=H3175): A Long GRB Localized by HETE
- GRB040422 : I-band follow-up observation at Lulin Observatory
- GRB 040422: ROTSE-IIIb Prompt Optical Limits
- GRB040422, BVRcIc field calibration
- GRB 040422,optical observation
- GRB 040422: a long GRB detected with INTEGRAL
- GRB 040403, deep optical observations
- MASTER: HETE Alert 3163, 3167 technical optical observation
- HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
- GRB 040403: Optical observations
- GRB 040403: a long GRB detected with INTEGRAL
- GRB040323: NIR Observations and Variable Object
- GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
- GRB 040323, a dark GRB ?
- GRB 040323: a long GRB detected with INTEGRAL
- GRB040223: Deep NIR NTT data re-analysis
- GRB 040223: XMM-Newton results
- GRB040223, improved XMM position
- GRB 031203, possible supernova
- MASTER: RXTE GRB040308 optical observation
- IBAS results on a burst from SGR1806-20
- INTEGRAL detection of activity from SGR1806-20
- RXTE GRB040229 optical observation: no candidate
- GRB 040228 Optical observations
- GRB040228 : KISO optical follow-up observation
- GRB 040223: Deep NIR NTT observations
- GRB 040223 : Optical observation (non-detection)
- XMM-Newton Images of GRB 040223
- GRB 040223, VLA observations
- GRB 040223: REM IJK Observations
- GRB 040223 XMM-Newton observation ...
- GRB 031203 XMM-Newton observation
- GRB 040223: further offline analysis
- GRB031111, optical observations
- GRB031220: 2nd Chandra observation and X-ray afterglow candidate
- GRB031203: Chandra Observations
- GRB040106: refined X-ray transient position
- SN 2003dh/GRB030329 late-time optical spectroscopy
- GRB 031220: Optical observations of Chandra X-ray sources
- XMM-Newton Images of GRB 040106
- GRB031220: observation at Univercity of Miyazaki
- XMM-Newton observation of GRB040106
- GRB 040106 : peak flux
- GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
- GRB031220(=H2976): Observation with the Chandra X-ray Observatory
- GRB031220: Palomar Observations
- GRB 031220 : Kyoto Optical Observation
- GRB 031220: Subaru observation
- GRB 031220: Optical observation at Tokyo Tech
- GRB 2974 follow-up observations
- GRB031203, improved XMM position
- GRB 021203: A Normal GRB viewed far off axis?
- XMM-Newton Observations of GRB031203: Preliminary Images
- GRB 031203: Variable Radio Source
- GRB 031203: Magellan spectrum of possible GRB host
- GRB 031203: Optical/IR Astrometry
- GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
- XMM-Newton Observation of GRB031203
- GRB031203: K' Photometry of the likely GRB host
- XMM-Newton Observation of GRB031203
- GRB 031203: IR NTTobservations do not confirm REM detection
- GRB031203 : Optical Observation of Lulin Observatory
- GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
- GRB 031203: Apparent Spectral Break
- GRB031203: Planned XMM-Newton observation II
- GRB 031203: IR REM Observations
- GRB031203: Optical Observations
- GRB 031203 XMM-Newton observation
- GRB031203: Planned XMM-Newton observation
- GRB 031203: further analysis of INTEGRAL data
- GRB 030329: Planned XMM-Newton Observation
- GRB 031111B (= H2925) : Kyoto Optical Observation
- IPN triangulation of GRB031114 (large error box)
- GRB 031111, optical observations
- GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
- GRB030929/SN2003jd association unlikely based on IPN localiztion
- IPN triangulation of GRB031027 (small error box)
- Lulin optical follow-up observations of GRB031026
- GRB 031026 (=H2882): Evidence for High Redshift from Prompt
- IPN triangulation of GRB031024 (single error box)
- IPN triangulation of GRB031024 (annulus)
- IPN triangulation of GRB031020 (large error box)
- XRF 030824: additional observations at CFHT
- SGR1806-20 bursts on 031008. Helicon detection and small error box.
- XRF 030723: Subaru Optical Observations
- XRF 030824: Early follow-up observation at Kiso observatory
- XRF 030824: observations at CFHT
- IPN triangulation of GRB030922B (large error box)
- XRF 030723: Detection of the likely host galaxy