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"12054 results found.
- GRB 041218 : Radio Observations
- GRB041015, optical observation in CrAO
- GRB041015 : Multi epoch optical observations
- GRB 041016: BOOTES-2 simultaneous observation
- GRB041006: RTT150 Optical Observations
- GRB 041016: Optical limits in V, R, I
- GRB041015 : Optical follow-up at Kiso
- GRB 041006: Radio Observations
- GRB041006, optical I observation
- ROTSE-IIIa Observations of GRB 041006
- GRB 040924: WSRT Radio Observations
- GRB040903, REM near-IR observation
- GRB 040903 - INTEGRAL data analysis
- ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
- GRB 040827 - Radio Observations
- GRB 030324: Detection and Color of Host Galaxy
- GRB 040511: NIR observations with REM
- GRB 040511: Optical limit
- GRB 040511: ROTSE-III Rapid Optical Upper Limits
- GRB 040223: REM IJK Observations
- GRB031220: 2nd Chandra observation and X-ray afterglow candidate
- GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
- GRB 031203: IR NTTobservations do not confirm REM detection
- GRB 031203: Apparent Spectral Break
- GRB 031203: IR REM Observations
- SN 2003jd (SN/GRB?) -- X-ray Observations
- GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
- SN 2003jd (SN/GRB?), Radio Observations
- GRB030329: radio observations at RT-22 (CrAO)
- XRF 020427: Gemini-South Spectroscopic Observations of the Host
- GRB021206 optical counterpart upper limit
- XRF030723: Re-analysis of ROTSE-III early images
- GRB030723: Upper limits from historical observations
- GRB 021004: HST observations
- GRB 030329: Optical limit (contemporaneous imaging)
- GRB 030329: Optical limit (contemporaneous photography)
- GRB030329: RTT150 optical observations and upper limit for a host
- GRB 030329: all-sky CCD images by K. Shiokawa immediately after the burst
- GRB030329: RTT150 optical observations and upper limit for a host
- GRB030329 observed as a sudden ionospheric disturbance (SID)
- GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
- GRB030418: Upper limits from recent and historical observations.
- GRB030329: HET spectroscopic monitoring
- GRB030328: R upper limit after 6 hours by MASTER
- GRB 030329: Light curve observed during the change of its slope.
- GRB 030329: Optical pre-Imaging
- GRB 030329: Upper limit from 5.6 hours before trigger
- GRB030329: Upper limits from recent and historical observations.
- RXTE detection of GRB 030329 afterglow
- GRB 030328: OT photometry
- GRB030323: Upper limits from recent and historical observations.
- IPN upper limit to a GRB associated with SN2003L
- GRB 030227: Optical limit at RIKEN
- GRB030226: Analysis of Chandra data
- GRB030227: Kiso optical upper limit
- GRB 030226: R band polarimetric observations
- GRB 20030226: Upper limits from recent and historical observations
- GRB 030226 simultaneous optical observations
- GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
- GRB030115 submm upper limit
- GRB 030115, simultaneous observations by BOOTES-1
- GRB 021211: R-band observations at late-time
- GRB021211, radio observations
- GRB021211: APO optical observations
- SUB-MM SEARCH FOR GRB 021211
- GRB 021211 Milagro GeV/TeV Observations
- GRB021211 - Upper limits from recent and historical observations
- GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
- GRB 021201: BOOTES simultaneous optical observations
- GRB 021004 submm observations
- GRB 021004 submm observations
- GRB 021004 - Unusual Radio-to-Submm Spectrum
- GRB021004: not fading anymore?
- GRB 021004: polarimetric observations
- IRAM Millimeter detection of GRB 021004
- GRB 021004: Optical observations at RIKEN
- GRB021004: Upper limits from recent and historical observations
- GRB 020813 multiband optical observations
- GRB 020625, optical observations
- AXP 1E2259+586: quasi-simultaneous optical observation
- GRB 020531, INT+WFC deep optical upper limits
- GRB 020531, simultaneous optical observations
- GRB 020418, optical/near-IR observations
- GRB020531: Upper Limit for Detection of Two TAROT Sources
- GRB020331: Optical Observations of Afterglow Candidate
- GRB011212: Optical Observations
- SN 2002ap - peak brightness date (SN/GRB?)
- GRB 020322: Optical Observations
- GRB 020305: Optical observations
- Type Ic SN2002bl (SN/GRB?) Radio Observations
- GRB020127: Further VLA Observations of Possible Counterparts
- IPN Upper Limits to a GRB Associated With SN2002ap
- GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
- GRB011212, Optical Observations
- Optical polarization observations for GRB011211
- GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
- GRB 011121: J-band observations
- GRB010921 - Milagro GeV/TeV Observations
- GRB 011121: HST Scheduled
- GRB 011030 R band observations