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').
- SGR 1808-20 (=H2802): A Possible new SGR
- GRB 021206 Optical Observations
- IPN triangulation of GRB030808 (two large error boxes)
- IPN triangulation of GRB030806 (large burst; large error box)
- XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
- IPN/HETE summary of recent bursts from SGR1806-20
- XRF 030723: Detection of a rebrightening in the optical afterglow
- GRB030725: Optical observations
- XRF030723, BVRcIc field photometry update
- IPN triangulation of GRB030801 (large error box)
- GRB021206 optical counterpart upper limit
- IPN triangulation of GRB030731 (annulus)
- IBAS GRB Alerts 1011-1017 NOT CONFIRMED
- XRF030723: Re-analysis of ROTSE-III early images
- IPN triangulation of GRB030725 (=H2779; small error box)
- XRF030723 (=H2777): Second Epoch Magellan Observations
- GRB 030725: optical observations.
- GRB030725, optical transient observations
- IPN triangulation of GRB030726 (large error box)
- IPN triangulation of GRB030722 (large error box)
- IPN triangulation of GRB030721 (large error box)
- XRF030723 Radio Observations
- XRF 030723: confirmation of fading optical counterpart
- XRF030723(=H2777): Chandra Observations
- XRF 030723: VLT spectra
- Magellan Observations of XRF030723 (=H2777)
- GRB030723: Upper limits from historical observations
- GRB030725, possible optical transient
- XRF030723: Palomar observations and proposed counterpart
- GRB030725 (=H2779): A Bright GRB Localized by HETE
- XRF030723: optical observations
- XRF030723 (= H2777): Chandra Observations Scheduled
- XRF030723, BVRcIc field photometry correction
- XRF030723, ROTSE-III Early Observations
- XRF030723, BVRcIc field photometry
- XRF 030723, optical observations
- XRF030723, optical observations
- XRF 030723, optical observations
- XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
- GRB030723, optical observations
- Konus-Wind detection of the bursts from SGR1806-20 region
- IBAS GRB Alerts 969 970
- SGR 1806-20, submm observations
- H2768, H2770, and H2771: Three Bursts from SGR1806-20
- IPN triangulation of GRB030717 (annulus)
- RXTE PCA Observations of SGR1806-20 Region
- GRB030329: Subaru Optical Spectroscopy
- Triangulation of GRB030715 (single large error box)
- Triangulation of GRB030714 (single large error box)
- 030716 NOT a GRB
- IPN triangulation of GRB030714 (two large error boxes)
- IPN triangulation of GRB030715 (two large error boxes)
- GRB030329: RTT150 optical observations
- GRBlog: Compilation of all GCN Circ. data
- IPN detection of renewed activity from SGR1806-20
- IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
- IPN triangulation of GRB030710 (annulus)
- IPN triangulation of GRB030709 (annulus)
- GRB030706 triangulation (single large error box)
- IPN triangulation of GRB030706 (annulus)
- IPN triangulation of GRB030629 (annulus)
- GRB030629 triangulation (Konus-Wind -- Helicon annulus)
- 030629 NOT a real GRB
- GRB030329, optical observation in May
- IPN triangulation of GRB030626 (single large error box)
- IPN triangulation of GRB030626 (two large error boxes)
- GRB030329: second XMM-Newton observation
- GRB030418: R optical observations
- HETE detection of burst from SGR1806-20
- GRB030329 -- RATAN-600 data in April-May
- Final IPN error ellipse for GRB021206 (the polarized GRB)
- GRB 021206, Radio afterglow candidate
- GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
- IPN triangulation of GRB030607 (annulus)
- IPN triangulation of GRB030606 (two alternate error boxes)
- GRB030329, SPM optical observations (Correction of GCN2075 R band)
- GRB 030528: Infrared Observations and the Proposed IR Counterpart
- IPN triangulation of GRB030605B (annulus)
- GRB 030528: Optical Observations
- IPN triangulation of GRB030605 (annulus)
- GRB 030528: tentative NIR counterpart
- GRB 030528, radio observations
- GRB030528(=H2724): Observations with the Chandra X-ray Observatory
- GRB030329, further radio observations at GMRT
- GRB030528, BVRI field photometry
- IPN triangulation of GRB030601 (annulus)
- GRB030329, SPM optical observations
- GRB030528: Chandra TOO Planned
- GRB 030519B: optical observations.
- MASTER: optical observation GRB030601
- GRB030528(=H2724): Revised SXC Localization
- GRB 030329: optical observations
- GRB 030329/SN 2003dh: Jitter Episode
- GRB 030528, Teramo optical observation
- GRB 030528 Bisei optical observation
- GRB030528 (H2724): A long GRB localized by HETE
- GRB 030329: Correction to GCN 2254
- GRB 030329: Optical Observations
- GRB 030528: Optical observations at RIKEN
- GRB 030528 (=H2724) Kyoto optical observation