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"- GRB030913: AAVSO optical observations
- GRB 030913, BOOTES observations
- GRB030913 (=H2849): Confirmation of the Flight Localization
- IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
- GRB030913 (=H2849): TAROT Observations
- GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
- Magellan Observations of GRB030725 (=H2779)
- GRB030913 (=H2849): A GRB Possibly Localized by HETE
- IPN triangulation of GRB030908 (annulus)
- GRB 030913: Optical limit at RIKEN
- XRF 020427: Gemini-South Spectroscopic Observations of the Host
- XRF030824: Optical observations
- IPN triangulation of GRB030903 (large error box)
- IBAS detection of bursts from SGR 1806-20
- Radio Observations of SGR1806-20
- IPN triangulation of GRB030831 (annulus)
- IPN triangulation of GRB030830 (large error box)
- GRB 030824: Candidate Follow-Up
- INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
- IPN triangulation of GRB030827 (large error box)
- GRB 030823 observation at Ouda
- XRF030824: Second-epoch Palomar observations
- XRF030824: optical observations
- IPN triangulation of GRB030822 (annulus)
- GRB030823: optical observations
- GRB030823: Palomar observations
- XRF030824: Palomar observations
- GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
- GRB030823: optical observation at Tokyo Tech
- RAPTOR observations of GRB030823
- Lulin follow-up observations of GRB030823
- IPN triangulation of GRB030821 (=H2814; refined error box)
- GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
- Summary of recent IPN and HETE detections of SGR bursts
- IPN triangulation of GRB030814 (annulus)
- Clarification of GCN 2354 on SGR1806-20
- IPN detection of continued activity from SGR1806-20
- 030813 SGR event (Konus-Wind observation)
- GRB 030817 = H2808 TAROT optical observations
- 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)