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"2803 results found.
- Oddball GRB 060218, transient or GRB?
- GRB060218: Swift/XRT Team preliminary analysis of the possible burst
- Brightening of the Optical Counterpart of the Possible GRB 060218
- GRB 060218: Pre-burst detection of a possible host galaxy
- GRB 060218A: ROTSE-III Possible Optical Flare
- GRB060218: Swift/XRT refined position of a possible burst
- Preliminary refined analysis of the Swift-BAT trigger 191157
- GRB 060218: Swift-BAT detection of a possible burst
- GRB060213: Swift XRT observations and possible afterglow candidate
- GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
- GRB 060211B: Swift/BAT refined analysis
- GRB 060209(?): Swift-BAT detection of a possible burst
- Orphan GRB Afterglow candidate
- GRB 060206: Swift-BAT refined analysis
- GRB 060204B: Swift-BAT refined analysis
- GRB 060203: P60 Confirmation of Optical Afterglow
- Possible GRB 060203: candidate optical counterpart
- Swift BAT Trigger 180151: Swift XRT source detection
- Possible GRB 060203: optical observations at Asiago
- Swift-BAT trigger 180151 is unknown origin at this time
- GRB 060121: Gemini Late-time Observations
- GRB 051211A: MDM Observations
- GRB 060123: Gemini spectroscopy of the putative host galaxy
- Possible GRB 051221B: MDM Correction
- GRB060105: refined analysis of the Suzaku observation
- GRB 060117: pseudo-z from spectral parameters of the prompt emission
- GRB 060116: possible I-J dropout
- GRB 060111B: MITSuME detection of optical afterglow
- GRB060111A: RTT150 optical observations
- GRB060111B: RTT150, possible host galaxy
- GRB 060111B: Swift detection of a burst
- GRB 060111: possible UVOT counterpart
- GRB 060110: Swift-BAT refined analysis
- GRB051211B: optical observations
- GRB 051227: Swift/UVOT Upper Limits (Possible U-band
- GRB 051227: Further analysis of the Swift-BAT burst
- Possible GRB 051221B: MDM Optical Detection
- Possible GRB 051221B: Swift XRT position
- Swift-BAT detection of a possible burst
- GRB 051221: Possible nearby cluster
- GRB051211A (=H3979): Refined Analysis
- GRB051211A: possible optical candidate
- GRB 051215: near-infrared observations
- GRB 051215: Swift detection of a possible burst
- GRB051105: optical observations
- GRB 051213: Swift-BAT detection of a burst
- GRB051211b: P60 Observations
- GRB 051211A and GRB051211B: BOOTES simultaneous observations
- GRB 051211B: a possible optical detection by TAROT
- HETE SXC localization of GRB 051211 (=H3979)
- IPN observations of SGR1806-20
- Possible resuming of the SGR 1806-20 activity
- GRB 051127: Swift-BAT detection of a possible burst
- GRB 051117B: R and I observations of possible host galaxy
- GRB 051111A: ROTSE-III Detection of Possible Counterpart
- GRB 051109: ROTSE-III Detection of Possible Counterpart
- GRB051103: optical observations
- Chandra Observations of GRB 051022
- GRB 051022, J & K-band observation
- GRB 051021: Optical observations and candidate afterglow
- Swift-BAT triggered on a posible CR Shower or possible GRB
- Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
- GRB051006: optical observations
- Swift-BAT Trigger 159578 is a possible burst
- GRB050805A: Rc optical observations
- GRB 051008 - a low redshift low-luminosity burst?
- GRB051011: bright nebulae near error box
- GRB 051008: Swift UVOT Candidate
- GRB 050906, summary of radio observations
- GRB 051001: ROTSE-III Optical Limits
- GRB/SGR 050925: IR Observations
- GRB050925: Swift-BAT detection of a short burst
- GRB 050922C: ROTSE-III Detection of Possible Counterpart
- GRB050922B: Swift-BAT detection of a weak long burst
- Possible GRB 050922 detected by INTEGRAL
- GRB050918: Possible Swift/XRT detected afterglow
- Swift trigger 155764: bad XRT centroid
- GRB050911: Swift-XRT position
- GRB 050911: z~0.16 cluster in the field
- GRB 050906: Possible X-ray Counterpart
- GRB 050908: Swift detection of a burst
- GRB 050906: Swift-BAT refined analysis
- GRB050906: P60 Observations
- GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
- GRB 050906: Bright galaxy in BAT error box
- GRB 050906: Swift/BAT Detection of a possible burst
- GRB 050904: Possible High-Redshift GRB
- GRB050904: Swift-BAT detection of a probable burst
- Retraction of Swift-BAT trigger #153355
- GRB 050827: P200 NIR Observations
- GRB 050827: XRT possible afterglow detection
- GRB 050826: BAT refined analysis
- Possible GRB050825:MASTER optical observations
- GRB 050824: XRT refined analysis and possible afterglow detection
- GRB 050820a - corrections to GCN 3846
- GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
- GRB050817: Negative Optical Observations
- GRB050817: Swift-BAT Detection of a burst
- GRB050815: Swift-BAT detection of a burst
- GRB 050813: Non-fading of afterglow candidate