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"2933 results found.
- GRB 090531: Swift detection of a burst
- GRB 090530: GRAS002 optical observations
- GRB 090515: KAIT optical upper limits
- GRB 090510B: Fermi GBM detection
- GRB 090426: optical observations
- GRB 090426: R-band limit
- GRB 090426: Swift detection of a burst with an optical counterpart
- GRB 090424: Liverpool Telescope observations
- GRB 090423 limiting magnitudes
- GRB 090418B: Detection of a bright burst from Swift-BAT slew data
- GRB 090417B: Swift-XRT refined analysis
- GRB 090411B: Suzaku WAM observation of the prompt emission
- GRB 090411B: Fermi GBM detection
- Swift-BAT trigger 348781: almost certainly not a burst
- GRB 090403: Fermi GBM detection
- GRB090401B, RIMOTS optical upper limits
- GRB 090401B: Swift detection of a burst
- GRB 090324: Suzaku WAM observation of the prompt emission
- GRB 090323: Swift-XRT refined analysis
- GRB 090313 - PAIRITEL NIR detections
- IPN localization of short GRB 090305C
- Konus-Wind observation of bright short GRB 090227B
- IPN localization of short bright GRB 090227B
- VLA radio upper limit on GRB 090205
- Konus-Wind observation of GRB 090201
- GRB 090201: Swift-XRT refined analysis
- GRB 090201: Swift detection of a burst
- GRB 090129: Swift-BAT refined analysis
- AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
- AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
- GRB 090113: LOAO Detection Limits in R, I, z, Y-band
- GRB 081230: ROTSE-III Detection of Optical Counterpart
- Konus-Wind observation of GRB 081222
- GRB 081217: Fermi GBM detection
- GRB 081210: Xinglong TNT R band Upper Limits
- IPN triangulation of short hard GRB 081209
- GRB 081203A: optical observations
- Swift-XRT observations of GRB 081203B
- Swift-BAT Trigger 334129: possible burst
- SGR 1806-20: Fermi GBM detection
- GRB 081024: Swift detection of a burst
- GRB 081017, Swift-BAT refined analysis
- GRB 081016B: ROTSE-III Optical Limits
- GRB 081016B: Swift detection of a burst
- Swift detection of flare on CC Eri
- Detection of flare star Algol in Swift-BAT slew data
- Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
- GRB 080928: Swift-XRT refined analysis
- GRB 080916B: Swift detection of a burst
- GRB 080903: optical observations
- GRB 080903: Liverpool Telescope observations
- GRB 080903: Astrotel-Caucasus optical observations
- GRB 080903: Optical afterglow candidate
- SGR 0501+4516: Decline in Activity
- Konus-Wind observations of new SGR 0501+4516
- INTEGRAL ToO Observation of SGR0501+4516
- Trigger 321551: Continued Large Flaring of SGR 0501+4516
- Swift Trigger 321481: A Large Flare from SGR 0501+4516
- GRB080810: optical observations
- GRB 080810: Swift/UVOT Refined Analysis
- GRB 080810: Liverpool Telescope observations
- GRB 080810: D50 optical observation
- GRB 080810: Observations from NOT
- GRB 080810: ROTSE-III Prompt Detection of Optical Counterpart
- GRB 080810: Keck/HIRES Spectroscopy
- GRB 080810: Swift detection of a burst with a bright optical afterglow
- GRB 080723B: XMM-Newton observation
- GRB 080727B: IR photometry
- GRB 080723B - Swift-XRT position
- GRB 080710: REM afterglow confirmation & brightening
- GRB 080707: VLT redshift
- GRB 080703: UVOT Follow-Up Observation
- GRB 080703: VLT observations of the afterglow
- GRB 080703: Swift detection of a burst with optical afterglow
- GRB 080703A: ROTSE-III Detection of Optical Counterpart
- GRB 080623: Swift XRT prompt analysis
- GRB 080613B: GROND Upper Limits
- GRB 080605: MASTER VWF 46 s AT observation
- GRB 080605: Swift detection of a burst with an optical afterglow
- Swift/UVOT observations of GRB080604
- GRB 080604: Early Super-LOTIS Observations
- GRB080604: confirmation of optical afterglow
- GRB 080604: Swift detection of a burst with an optical afterglow
- Konus-Wind observation of reactivation of SGR 1627-41
- Reactivation of SGR 1627-41
- IPN triangulation of bright GRB 080513
- GRB 080503: Chandra Observation of X-ray Rebrightening or Flattening
- GRB 080503: Late-time Optical rebrightening (possible mini-SN)
- GRB 080503: Enhanced Swift-XRT position
- GRB 080503: New candidate afterglow/host in Gemini imaging
- GRB 080503: Swift detection of a short burst
- Swift-BAT trigger 309665 is not a GRB
- GRB 080420?: Swift detection of a possible short burst
- GRB 080413A, Swift-BAT refined analysis
- GRB080330: MAGIC telescope GeV observation
- GRB 080405: Swift-BAT refined analysis
- GRB 080328: Swift detection of a burst with an optical counterpart
- GRB 080320: Early Super-LOTIS Observations
- GRB 080319A/B/C: INTEGRAL SPI-ACS light curves available
- GRB 080319b light curve by Pi-of-the-Sky