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"- Konus-Wind observation of GRB 080204
- GRB 080205 optical upper limit
- GRB 080205: MASTER optical observation
- GRB 080205: optical observation
- VLA radio upper limit on GRB 080205
- INT+WFC R-band observations of GRB 080205
- GRB 080205, Swift-BAT refined analysis
- IPN localization of very hard GRB 080204
- GRB 080205: Swift XRT refined analysis
- GRB 080205: OA evolution from KAIT observations
- GRB 080205: Swift/UVOT observations
- GRB 080205: Enhanced Swift-XRT position
- GRB 080205: KAIT OA detection
- GRB 080205: Swift detection of a burst
- Swift-BAT Trigger #302454, correction of GCN notice, update on AX J1749.1-2639
- GRB 080130: Swift-BAT refined analysis
- GRB 080130: further Swift XRT observations confirm fading source
- GRB 080129: Swift/UVOT Refined Upper Limits
- Swift/UVOT observations of GRB080130
- GRB 080130: REM NIR observations
- GRB 080130(?): Swift XRT observation
- GRB 080130?: Detection of a possible burst by BATSS
- GRB 080129: Optical observations from OSN
- GRB 080129: Swift-XRT refined analysis
- X-ray transient in NGC 2770: RTT150 optical observations
- GRB 080129: KAIT optical limits
- GRB 080123: Early afterglow detection with BATSS (BAT Slew Survey)
- GRB 080129: optical limit by Pi of the Sky
- GRB 080129, Swift-BAT refined analysis
- GRB 080129: TAROT La Silla observatory optical observations
- GRB 080129: Gemini-South photometry
- GRB 080129: GROND detection in all bands, and fading
- GRB 080129: GROND detection of the optical/NIR afterglow, and fading
- GRB 080129: Enhanced Swift-XRT position
- GRB 080129: Gemini-South Imaging Observations
- GRB 080129: Swift XRT position
- GRB 080129 (?): UVOT Upper Limits
- GRB 080129 (?): Swift detection of a possible burst
- A new website of high-level data products for Swift GRBs
- GRB 080121: Upper limit on X-ray afterglow
- GRB 080123 : Suzaku WAM observation of the prompt emission
- Swift trigger(=301779) is not a GRB
- Transient 080109/SN 2008D: Spectroscopic Evolution
- GRB 080122: pseudo-z= 1.93 from prompt emission spectrum
- Konus-Wind observation of GRB 080122
- GRB 080122 : Suzaku WAM observation of the prompt emission
- GRB 080121: Swift/UVOT upper limits
- SNe 2008D and 2007uy: Chandra Detections
- GRB 080121 position was incorrect
- GRB 080121: Enhanced Swift-XRT position
- Two non-burst Swift SubThreshold triggers
- Transient 080109/SN 2008D: Spectroscopic Evolution and Re-Classification
- IPN triangulation of GRB080122
- GRB 080121: Nearby SDSS galaxies
- GRB 080121: Swift-BAT detection of a very weak, short burst
- GRB 080123: Swift-XRT refined analysis
- GRB 080123: Swift/UVOT refined analysis
- X-ray transient in NGC 2770: RTT150 optical observations
- GRB 080123, Swift-BAT refined analysis
- GRB 080123: Enhanced Swift-XRT position
- GRB 080123: Swift detection of a short burst
- GRB 080120: GROND confirmation of the optical afterglow
- XRF 080109 / SN 2008D: GMRT radio observation at 1280 MHz
- VLA radio upper limit on GRB 080120
- GRB 080120: Swift-XRT refined analysis
- UVOT detection of GRB080120
- GRB 080120: GROND detection
- GRB 080120 : Planned XMM-Newton observation
- GRB080120: Swift XRT position
- GRB 080120: a long GRB detected by INTEGRAL
- XRF 080109 / SN 2008D: 1.4 GHz WSRT Radio Observations
- Transient in NGC2770 / SN2008D: Metallicity of nearby HII regions
- Transient XRF 080109 / SN 2008D: Mount Abu NIR observations
- XRF 080109 / SN 2008D: WSRT Radio Detection
- Transient 080109/ SN 2008D, metallicity of the host galaxy
- Transient 080109/ SN 2008D, IR Spectrum
- XRF 080109 / SN 2008D: optical observations
- NGC 2770B has the same redshift as NGC 2770
- Swift UVOT Monitoring of the SN 2008D Brightening (Transient in NGC 2770)
- XRF 080109 / SN 2008D: spectroscopic evolution
- XRF 080109 / SN 2008D: UKIRT JHK imaging
- optical observations, XRT in NGC 2770
- XRF 080109/SN 2008D: PROMPT Optical Imaging
- Gemini-South observations of XRF 080109 / SN 2008D
- Swift observations of the X-ray transient in NGC 2770 (aka SN2008D)
- Discovery of Radio Emission from Transient in NGC 2770
- XRF 080109 in NGC2770: NIR observations at TNG
- XRB 080109/SN 2008D: Early decline in brightness and change in colors
- XRB 080109/SN 2008D:PAIRITEL NIR observations and t_0 from Swift
- XRF 080109 in NGC2770: Detectable Superluminal Motion
- Detailed Spectroscopic ID of SN 2008D (Transient in NGC 2770)
- XRF in NGC 2770: Search for X-ray periodicity
- Spectroscopic classification of SN 2008D (Transient in NGC 2770)
- Refined Swift-XRT analysis of the transient in NGC 2770
- Transient in NGC 2770: spectroscopic evidence for a SN
- Refined Swift UVOT Analysis of SN 2008D (Transient in NGC 2770)
- Opticall follow-ups for the X-ray transient in NGC 2770
- X-ray transient in NGC 2770: Optical observations with Astrotel-Caucasus
- Optical Spectroscopy of the Transient in NGC 2770
- Swift UVOT Observations of the X-ray transient in NGC 2770