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"3758 results found.
- GRB 050807: ROTSE-III Optical Limits
- GRB050730: Radio Detection
- GRB050803: MASTER further analys
- GRB050803: MASTER optical observations
- GRB 050801: Swift-BAT refined analysis
- GRB050801: Swift-BAT detection of a burst
- GRB 050801: ROTSE-III Detection of Possible Counterpart
- GRB 050721A: Early Swift XRT analysis results
- GRB 050721: optical afterglow confirmed
- GRB050716, optical observation
- Limits on a SN in the field of GRB 050509b
- Konus-Wind observation of GRB 050603
- Swift-BAT detection of possible GRB 050528
- GRB 050509b: refined XRT/Chandra afterglow position analysis
- GRB050525: Optical observations
- RBO Observations of GRB050520
- GRB 050509b: Keck/Chandra Cross-Correlation
- GRB 050509b: Keck/Chandra Cross-Correlation
- Chandra observation of GRB 050509b
- GRB 050509b: Swift/UVOT follow-up measurements
- GRB050509B: Optical observations at the Very Large Telescope
- GRB 050509a: Swift-BAT refined analysis
- GRB 050509b: Further Analysis of Keck LRIS Images
- GRB 050509B: Swift/XRT refined analysis
- GRB 050509b: Precision Astrometry
- GRB 050509b: Possible Optical Counterpart
- Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
- GRB 050509b: PAIRITEL and WIYN Observations
- GRB 050509b: Swift-BAT refined analysis of the short hard burst
- GRB 050509b: Swift XRT Position
- GRB 050509a: Swift XRT Position
- Swift Detection of the Burst GRB050509
- Swift-BAT detection of GRB 050507
- GRB 050502a: Swift XRT Upper Limit
- GRB 050502A: WSRT Radio Observations
- Swift Detection of GRB050421
- GRB050418: Null Optical Observations
- GRB 050412: optical observations
- GRB 050401: Optical limit
- GRB 050408: Optical limit
- GRB 050406: early Swift XRT analysis results
- GRB 050406 BAT refined analysis
- GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
- GRB050331: No Afterglow Detected
- GRB050319: BR optical photometry
- GRB 050319 : Confirmation of optical afterglow decay
- GRB050223: analysis of the XMM-Newton observation
- GRB050309: CONCAM pre-trigger and trigger coincident optical
- GRB 050306: REM optical-infrared observations
- Swift trigger 107518: optical observation
- GRB050215B: Late-Time Swift UVOT Observations
- GRB050223 XMM-Newton observation
- GRB 050223 : Planned XMM-Newton observation
- GRB050223: No Swift UVOT Detection of Afterglow Emission
- GRB 050223: Swift XRT Position
- Swift-BAT detects two bursts: GRB050215a and GRB050215b
- GRB 050128 Optical observation with REM
- GRB 050128: near-infrared observations with REM
- GRB050128,optical observations
- GRB 050128: Swift XRT prompt afterglow position
- GRB050126: MASTER optical limit for KECK OT
- SGR1806: Optical Transient Candidates in SOHO/LASCO Images
- Further VLA observations of SGR 1806-20
- SGR 1806-20, RHESSI observations of the 041227 giant flare
- SGR1806-20: RXTE-PCA observation of the 041227 super-flare
- GRB041228: ROTSE-III Optical Observations
- GRB 041219: TAROT optical observations
- GRB041223: Swift-BAT detection of a bright long burst
- Very high activity of SGR 1806-20
- GRB041217: NIR and optical observations with REM
- GRB041217: The First GRB Located On-Board Swift
- Konus-Wind observation of a series SGR 1806-20 bursts on 041005
- GRB040929,optical observation
- Optical observations of field of GRB040912
- Very bright burst detected from SGR 1806-20
- GRB040827 XMM-Newton observation
- GRB040825A: optical limit before GRB
- XRF040701: Second-Epoch Chandra Observations
- XRF040701: First-Epoch Chandra Observations
- GRB040709 J,H-band observations
- Optical Observations of GRB040624
- IPN Summary of SGR1806-20 Activity in 2004
- MASTER:HETE Alert 3259 (SRG1806-20) optical observation
- SGR 1806-20, potential NIR counterpart
- GRB040228 : KISO optical follow-up observation
- GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
- GRB 040223: a long GRB detected with INTEGRAL
- GRB 031220: Optical observations of Chandra X-ray sources
- IPN triangulation of an intermediate burst from SGR1806-20
- GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
- GRB 031203: Discovery of a dust echo
- GRB 031203: A long GRB detected with INTEGRAL
- GRB 031111: Optical observations
- XRF031109 (=H2919): A very long XRF localized by HETE
- IPN triangulation of GRB031027 (small error box)
- Lulin optical follow-up observations of GRB031026
- SN 2003jd (SN/GRB?) - possible association with GRB 030929
- GRB031026 : KISO optical follow-up observation
- IPN triangulation of GRB030926 (short/hard; large error box)
- IPN triangulation of GRB030922A (large error box)