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"32532 results found.
- IPN triangulation of GRB031024 (single error box)
- GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
- XRF 030824: additional observations at CFHT
- SGR1806-20 bursts on 031008. Helicon detection and small error box.
- SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
- XRF 030723: Subaru Optical Observations
- XRF 030824: Early follow-up observation at Kiso observatory
- XRF 030723: Detection of the likely host galaxy
- XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
- XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
- IPN triangulation of GRB030922A (large error box)
- IPN triangulation of GRB030921 (large error box)
- GRB030913: Subaru Optical Observations
- GRB 030913: ROTSE-3c Optical Observations
- GRB030913: OT's limit by MASTER
- GRB030913, candidate afterglow observations
- GRB030913: AAVSO optical observations
- GRB030913 (=H2849): Confirmation of the Flight Localization
- GRB030913 (=H2849): TAROT Observations
- Magellan Observations of GRB030725 (=H2779)
- GRB030913 (=H2849): A GRB Possibly Localized by HETE
- IBAS detection of bursts from SGR 1806-20
- Radio Observations of SGR1806-20
- GRB 030824: Candidate Follow-Up
- XRF030824: Second-epoch Palomar observations
- XRF030824: optical observations
- XRF030824: Palomar observations
- GRB030823: optical observation at Tokyo Tech
- RAPTOR 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
- Clarification of GCN 2354 on SGR1806-20
- IPN detection of continued activity from SGR1806-20
- 030813 SGR event (Konus-Wind observation)
- SGR 1808-20 (=H2802): A Possible new SGR
- GRB 021206 Optical Observations
- 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
- GRB021206 optical counterpart upper limit
- 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
- 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
- XRF030723, optical observations
- XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
- Konus-Wind detection of the bursts from SGR1806-20 region
- SGR 1806-20, submm observations
- 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)
- GRB030329: RTT150 optical observations
- GRBlog: Compilation of all GCN Circ. data
- GRB030706 triangulation (single large error box)
- GRB030329, optical observation in May
- IPN triangulation of GRB030626 (single large error box)
- GRB030418: R optical observations
- Final IPN error ellipse for GRB021206 (the polarized GRB)
- GRB 021206, Radio afterglow candidate
- GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
- GRB 030528: Infrared Observations and the Proposed IR Counterpart
- GRB 030528: Optical Observations
- GRB 030528: tentative NIR counterpart
- GRB 030528, radio observations
- GRB030329, further radio observations at GMRT
- GRB030528, BVRI field photometry
- GRB030329, SPM optical observations
- GRB030528: Chandra TOO Planned
- GRB 030519B: optical observations.
- 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 030416: Optical Observations
- GRB030329, Optical observations
- GRB 030329/SN 2003dh: Possible increase in brightness
- GRB 030329: HST ACS Observations of the Host
- GRB 030329 Optical Observations
- GRB030329: XMM-Newton observation
- GRB030324: Further Observations of the Candidate Optical Afterglow