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"26781 results found.
- GRB050209: REM optical observations
- GRB 050209 Optical observations
- GRB050209: P60 Optical Observations
- GRB 050209: Optical observation
- Further analysis of the short Swift-BAT GRB 050202
- GRB 050202: Second epoch radio observations
- GRB050202: Radio Observations
- GRB 050202: Short burst detected by Swift-BAT
- SGR1806-20: Swift-BAT detection of a large normal burst
- GRB050128: Faulkes Telescope South observations
- GRB050128,optical observations
- GRB050128 Swift-BAT observations
- GRB 050128: Swift XRT prompt afterglow position
- GRB050126: MASTER optical limit for KECK OT
- GRB050126: Burst Parameters Measured by BAT
- GRB 050126: Prompt XRT detection and localization
- GRB 050124 I-band observation
- GRB050124,optical observation
- GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
- GRB050124: Refined BAT position, spectral and fluence information
- GRB050124: Swift-BAT position of a double-peaked burst
- GRB050123,optical observation
- GRB 050123: KAIT observations
- GRB 050123(=H3666): A GRB Localized in Real Time by HETE
- GRB050117a: Refined analysis
- GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
- GRB050117b: Swift-BAT detection of a weak burst
- GRB 050117, I-band observations
- GRB050117: Swift-BAT detection of a long multi-peaked burst
- GRB050117: Swift XRT Position
- SGR1806-20: Swift-BAT observations of two additional bursts
- SGR 1806-20, RHESSI observations of the 041227 giant flare
- SGR1806-20: RXTE-PCA observation of the 041227 super-flare
- SGR1806-20: Swift-BAT observation of the 041227 super-flare
- The giant outburst from SGR 1806-20
- GRB041228: Swift-BAT detection of a burst
- GRB041219; RXTE ASM Observations
- NIR Observations of GRB 041219
- GRB041226: Swift-BAT detection of a burst
- GRB 041224: near-infrared observations with REM
- GRB 041223 Fluence measured by Swift-BAT
- GRB041224: Swift-BAT detection of a soft burst
- Swift-BAT Time History of GRB041219
- GRB041223: Swift XRT Detection of X-ray Afterglow Emission
- GRB041223: Swift-BAT detection of a bright long burst
- GRB041220: Swift-BAT burst
- Deep RAPTOR observations during GRB 041219
- GRB041219c: Third Burst in One Day from Swift-BAT
- GRB041219b: A Swift-BAT burst
- GRB 041219 ,optical observation
- GRB 041218: R-band optical observations
- Swift-BAT detection of the bright long burst GRB041219
- GRB041219: Prompt Optical Observations from ROTSE-IIIb
- GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
- GRB041217: The First GRB Located On-Board Swift
- GRB041211: RAPTOR observations
- GRB041211, BVRcIc field calibration
- GRB041211,optical observation
- GRB 041211: KAIT observations
- Distribution of IBAS Alerts for NON-GRB sources
- GRB 041006: GETS Optical Afterglow Observation
- Summary of the recent bursts from SGR 1806-20
- GRB041015, optical observation in CrAO
- Bright bursts from SGR1806-20
- GRB 041016: BOOTES-2 simultaneous observation
- GRB041016,optical observation
- GRB 041016: Optical limits
- GRB 041016:Optical limit during first minute
- GRB041016: MASTER: Optical observations
- GRB041006: Near Infrared observations
- GRB 041016: Optical limit
- GRB 041015 R band observations
- GRB040924, BVRcIc field calibration
- GRB041015: MASTER: Optical observations
- GRB041015,optical observation
- GRB041006: MASTER optical observations
- GRB041006,optical observation
- GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
- Konus-Wind observation of a series SGR 1806-20 bursts on 041005
- GRB040929,optical observation
- GRB040924,optical observation
- GRB040924: KAIT observations
- GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
- GRB040924 (H3564): Optical afterglow candidate
- XRF040912, BVRcIc field calibration
- XRF040916, BVRcIc field calibration
- GRB040916: Optical observations
- GRB/XRF040912,optical observations
- GRB 040912, BVRI observations
- Optical observations of field of GRB040912
- HETE 3557: Optical observations
- GRB040825B, BVRcIc field photometry
- GRB040825A, BVRcIc field photometry
- GCN GRB OBSERBATION REPORT
- GRB 040825A,optical observations
- Increase of SGR 1806-20 activity
- GRB040825A: optical observations
- GRB040825B: optical observations
- GRB040825B (=H3510): An XRF Localized in Real Time by HETE
- GRB 040825A: Optical observations.