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"11375 results found.
- GRB 030324, optical observations
- IPN triangulation of GRB030317 (annulus)
- GRB 030227: Optical limit at RIKEN
- IPN triangulation of GRB030306 (single small error box)
- IPN triangulation of GRB030306 (two small error boxes)
- IPN triangulation of GRB030306 (intense; annulus only so far)
- GRB030226: Analysis of Chandra data
- GRB 030227: fading of candidate optical afterglow 'S1-A'
- GRB 030227, possible optical counterpart of XMM-Newton source
- GRB030227 - faint tentative OT candidate
- GRB 030227: Kyoto optical observation
- GRB030227 localized by INTEGRAL
- GRB 030226, optical observations
- GRB 030226 Optical Spectra and R,I,z' Imaging
- GRB030226: Candidate optical afterglow
- GRB 030217: Optical Observations at 4, 5, and 6 Days
- GRB030217: optical observations
- GRB030131: Kiso optical limit for corrected position
- GRB030131: Optical limits for corrected position
- GRB 030131: afterglow candidate
- GRB030131: Optical limit
- GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
- GRB 030115, simultaneous observations by BOOTES-1
- GRB030115: R-band counterpart of IR candidate
- GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
- GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
- GRB030115: R-band observations at Asiago
- GRB 030115: APO Optical Observations
- GRB 030115, no optical candidate
- IPN triangulation of GRB030102B (portion of annulus)
- GRB on 20030101 seen by SPI-ACS
- IPN triangulation of GRB021219
- GRB021219: a long GRB localized by INTEGRAL
- IPN detection of continued activity from SGR1806-20
- GRB 021201: Optical Observations
- GRB 021211: early break in light curve
- GRB021211: Optical observations in CrAO
- Chandra observation of the IPN error box of GRB021201 (short/hard)
- GRB 021211 Milagro GeV/TeV Observations
- GRB021211, OT at 108 s
- GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
- HETE 2493: Optical observations
- IPN triangulation of GRB021206 (exceptionally bright; annulus only)
- IPN detection of renewed activity from SGR1806-20
- GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
- IPN detection of continued SGR1900+14 activity
- Improved IPN error box for GRB021125
- GRB021125 : A long GRB localized by INTEGRAL
- IPN confirmation of the reactivation of SGR1900+14
- IPN detection of possible reactivation of SGR1900+14
- IPN triangulation of GRB021119 (annulus)
- GRB021112: Optical Observations
- GRB021113 (=H2449): A Long GRB Localized by HETE
- GRB021112 (=H2448): A Long GRB Localized by HETE
- IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
- SGR1900+14 activity, November 2-4, 2002
- Detection of activity from SGR 1900+14 with the RXTE/PCA
- GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
- GRB 021004: optical observations
- IPN triangulation of GRB021020 (smaller error box)
- GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
- IPN triangulation of GRB021020
- GRB 021016, optical observations
- GRB 021004: VRI observations at TNG: possible break
- GRB 021008, optical observations
- GRB021016(=H2397): A Long GRB Localized by HETE
- GRB021004: NIR and Optical observations
- GRB 021004: Optical measurement at OHP
- GRB 021004: optical spectroscopy
- GRB021004: BVRc photometry
- GRB 021004: Optical Photometry at 2.5 Days
- GRB 021004 radio observation
- GRB 021004: Optical Observations
- GRB 021004: Optical Photometry at 1.5 Days
- GRB021004, Optical Observations
- GRB 021004, optical observations
- GRB 021004, SPM optical observations
- GRB 021004: steepening of the optical decay slope
- XRF020903, BVRI field photometry
- GRB 020903: Optical observations at RIKEN
- XRF 020903: Supernova
- IPN triangulation of GRB020926 (two large error boxes)
- GRB020924 (ecliptic latitude-only localization)
- IPN triangulation of GRB020923 (two error boxes)
- Improved IPN position for GRB020918 (two large error boxes)
- IPN triangulation of GRB020911 (2 large error boxes)
- IPN detection of a burst from SGR1900+14
- INTEGRAL GRBs added to GCN
- GRB020812: optical observation
- Second epoch K band imaging of GRB 020819
- GRB 020812: early time optical observation at Ouda Station
- GRB020813: Magellan BVRI Photometry
- GRB 020819 : OT candidate - confirmation of non variability
- K band observation of GRB 020819
- GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
- IPN triangulation of GRB020819 (HETE 2275)
- GRB020813: Fading X-ray Afterglow Observed with Chandra
- GRB020812: NIR observations
- GRB020812: optical observations
- GRB 020812 : optical afterglow candidate