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"27289 results found.
- GRB050117: Refined XRT position
- GRB050117: MASTER optical observations
- MASTER:GRB050117 SWIFT
- GRB050117: Swift-BAT detection of a long multi-peaked burst
- GRB050117: Swift XRT Position
- SGR 1806-20: Further low frequency GMRT results
- SGR1806-20: Swift-BAT observations of two additional bursts
- SGR1806: Optical Transient Candidates in SOHO/LASCO Images
- SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
- SGR 1806-20, RHESSI observations of the 041227 giant flare
- Second-epoch VLA observations of SGR 1806-20
- SGR1806: Detection of a Sudden Ionospheric Disturbance
- DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
- SGR1806 VLA Observations
- SGR1806-20: RXTE-PCA observation of the 041227 super-flare
- GRB 041217: Optical observations
- SGR1806-20: Swift-BAT observation of the 041227 super-flare
- Detection of the SGR 1806-20 giant outburst back-scattered by the
- GRB041228: ROTSE-III Optical Observations
- GRB041228: Swift-BAT detection of a burst
- GRB041219; RXTE ASM Observations
- NIR Observations of GRB 041219
- GRB041226: ROTSE-III Optical Observations
- GRB041226: Swift-BAT detection of a burst
- GRB041223: decay of the afterglow
- GRB041224: ROTSE-III Optical Observations
- GRB 041223: XRT afterglow spectrum and light curve
- GRB 041223 Fluence measured by Swift-BAT
- GRB041224: Swift-BAT detection of a soft burst
- GRB041223: optical and NIR observations with REM
- Swift-BAT Time History of GRB041219
- GRB 041223: Detection of Optical Transient with LCO40
- GRB041223: Swift XRT Detection of X-ray Afterglow Emission
- GRB041223: ROTSE-III Optical Observations
- GRB041223: Swift-BAT detection of a bright long burst
- GRB 041219: WSRT Radio Afterglow Detection
- GRB 041218: Optical observations
- GRB041220: Swift-BAT burst
- GRB 041219 Optical Observations
- GRB041219c: Third Burst in One Day from Swift-BAT
- GRB041219: Optical Afterglow Detection
- GRB041219b: A Swift-BAT burst
- GRB 041219: Radio Afterglow Detection
- Swift-BAT detection of the bright long burst GRB041219
- GRB 041219: Infrared Afterglow Candidate
- GRB 041219: Infrared Afterglow Candidate
- GRB041217: optical limit 30 min after GRB
- GRB 041217: LCO40 Optical Observations and Possible Candidates
- GRB041217: Optical Observations
- GRB041217: NIR and optical observations with REM
- GRB041217: P60 Optical Observations
- GRB041217: Infrared Observations
- GRB041217: The First GRB Located On-Board Swift
- Distribution of IBAS Alerts for NON-GRB sources
- GRB041006: RTT150 Optical Observations
- GRB041006: RTT150 Optical Observations
- GRB 041006: SARA afterglow observations
- GRB 040924: detection of possible host galaxy by Subaru
- GRB 040924, optical follow-up
- GRB040916: Optical observations
- GRB040903, REM near-IR observation
- XMM-Newton Images of GRB 040827
- GRB 040827: optical and NIR observations at the VLT
- GRB 040827: Detection of NIR afterglow
- GRB 040827: Possible detection of optical afterglow
- CXO observation of GRB 040812
- GRB 040812: radio observations
- GRB040624: optical monitoring at TNG
- XRF040701: VLA Observations
- GRB 030324: Detection and Color of Host Galaxy
- GRB040511: Redshift identifcation
- GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
- GRB040422: optical and NIR observations at the VLT
- HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
- GRB040223, improved XMM position
- INTEGRAL detection of activity from SGR1806-20
- GRB 040223 : Optical observation (non-detection)
- GRB040106, likely optical afterglow
- GRB031203: K' Photometry of the likely GRB host
- GRB 031203: Radio detection
- GRB 031203: IR NTTobservations do not confirm REM detection
- IPN detection of activity from SGR1806-20
- SN 2003jd (SN/GRB?) - possible association with GRB 030929
- SGR1806-20 bursts on 031008. Helicon detection and small error box.
- IPN detection of continued activity from SGR1806-20
- XRF 030723: Subaru Optical Observations
- XRF 030723: Detection of the likely host galaxy
- GRB 030913, optical candidate
- XRF 020427: Gemini-South Spectroscopic Observations of the Host
- IBAS detection of bursts from SGR 1806-20
- GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
- IPN detection of continued activity from SGR1806-20
- XRF 030723: Detection of a rebrightening in the optical afterglow
- XRF030723: Re-analysis of ROTSE-III early images
- GRB 030725: optical observations.
- GRB030725, optical transient observations
- XRF030723 Radio Observations
- GRB030725, possible optical transient
- XRF030723: Palomar observations and proposed counterpart
- XRF 030723, optical observations