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"2910 results found.
- SGR 1806-20: continued moderate activity seen with INTEGRAL
- GRB051012: Swift-XRT analysis
- GRB 051021B: Refined analysis of the Swift-BAT burst
- GRB 051021: SOAR NIR Observations
- Swift-BAT triggered on a posible CR Shower or possible GRB
- GRB 051012: Swift-BAT detection of burst yesterday
- GRB 050922B: optical limit
- GRB 050906: Possible X-ray Counterpart
- GRB 050906: MARGE Optical Limits
- GRB 050824: MDM Observations
- GRB050824: First 2 hours of power low optical decay?
- GRB050824: MASTER final analysis of the OT observations
- GRB050822: Swift/UVOT upper limits
- GRB050813: Maidanak I-band observations
- GRB 050822: Swift detection of a long burst
- GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
- GRB050803: CrAO optical observations, no OT candidate
- GRB 050805b: OHP optical limits
- GRB 050803: Magellan Observations
- GRB 050803: early Swift XRT analysis results
- GRB 050730: OHP optical observations
- GRB 050802: early Swift XRT analysis results
- GRB 050802: Swift/UVOT observations
- GRB 050802: XRT position
- Swift-BAT trigger 147918 is not a real GRB
- Swift BAT Trigger 146986 is SWIFT J1753.5-0127
- GRB050716, optical observation
- GRB 050713, R-band observations at NOT
- GRB050607: prompt REM observations
- GRB050525: Super-LOTIS observations
- GRB 050525: Optical observation
- XRF050522: NIR observations of XRT candidate
- XRF 050522: Swift XRT refined analysis
- GRB050502b: Early Observation
- GRB 050505, early TAROT observation
- GRB050509a: Swift UVOT observations
- GRB 050509a: Swift XRT Position
- Swift Detection of the Burst GRB050509
- GRB 050505: Keck I-band Magnitude
- GRB 050505: early time observations
- GRB (?) 050504: IR Observations, Intriguing Source
- GRB050326: optical limit
- Swift Detection of GRB 050319
- RXTE Observations of GRB050318
- GRB050309: CONCAM pre-trigger and trigger coincident optical
- GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
- GRB 050219b: Swift XRT Position
- GRB050215b: Swift UVOT Detection of Afterglow Emission
- GRB 050215b: XRT confirmation of IR afterglow candidate
- GRB 050215B: candidate afterglow
- GRB 050215B: UKIRT K-band imaging
- GRB 050215b: Swift XRT Observations
- GRB050126: MASTER optical limit for KECK OT
- GRB050126: MASTER optical observations
- GRB050117: Palomar WIRC Ks-band observations
- GRB 041217: Optical observations
- GRB041226: ROTSE-III Optical Observations
- GRB041218: Continued P60 Optical Observations
- GRB 041218: Optical observations
- GRB041211,optical observation
- GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
- SGR 1806-20 still active
- GRB040924,optical observation
- IBAS GRB Alerts 1978-1980
- GRB040903 - A XRF?
- XRF040812: GMRT observations
- GRB 040812: Optical counterparts of CXO sources
- GRB 040812: Keck and LCO optical observations
- GRB 040812: Keck and LCO observations
- GRB040624: optical monitoring at TNG
- XRF040701: Second-Epoch Chandra Observations
- XRF040701: VLA Observations
- XRF040701: First-Epoch Chandra Observations
- IPN Summary of SGR1806-20 Activity in 2004
- MASTER: HETE Alert 3274 optical observation
- GRB040511: Candidate optical/NIR afterglow
- GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
- GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
- GRB031220: 2nd Chandra observation and X-ray afterglow candidate
- GRB040106: refined X-ray transient position
- GRB040106, Radio Observations
- GRB040106, likely optical afterglow
- GRB 040106: Optical observations
- XMM-Newton observation of GRB040106
- GRB 040106 : Planned XMM-Newton observation
- GRB 040106 : a long GRB detected with INTEGRAL
- GRB031220: Palomar Observations
- GRB 031203: IR NTTobservations do not confirm REM detection
- SN 2003jd (SN/GRB?) -- X-ray Observations
- IPN triangulation of GRB031016 (two large error boxes)
- XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
- IPN triangulation of GRB030921 (large error box)
- IPN triangulation of GRB030806 (large burst; large error box)
- XRF030723, ROTSE-III Early Observations
- XRF030723, optical observations
- XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
- IPN triangulation of GRB030715 (two large error boxes)
- GRB030329 -- RATAN-600 data in April-May
- GRB 030329: Optical limit (contemporaneous imaging)
- XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM