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"2797 results found.
- GRB 070810B: further XRT analysis
- GRB 071003: Keck spectroscopy
- GRB 071003: Possible rebrightening
- GRB 071003: Keck HIRES spectroscopy
- GRB 071003: MARGE Observations
- GRB070925: Swift-XRT Afterglow confirmation
- GRB 070917: Confirmation of the X-ray afterglow
- Swift Status and XRT Calibration Uncertainties
- GRB 070913: Swift-XRT detection of the possible X-ray afterglow
- Observations of possible TAROT GRB transient near IC 4779
- Las Campanas observations of possible TAROT GRB transient near IC
- Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
- Swift observatory off line
- GRB 070810A: Continued Keck Imaging
- GRB 070810B: Keck spectroscopy of possible host galaxies
- GRB 070810B: XRT refined analysis
- GRB070810B: Optical observations with KANATA
- GRB 070810B: Swift detection of a short burst
- GRB 070809: Keck Imaging
- GRB 070810: Swift detection of a burst
- GCN Swift XRT update position notices and enhanced position circulars
- GRB070612A: Radio upper limit from GMRT
- GRB 070729: LCO optical imaging
- Four radio sources in Swift-XRT error box of GRB 070724
- GRB 070721: Swift detection of a possible burst
- Swift detection of a possible burst (Trigger 284850)
- GRB 070611: VLT observations
- GRB 070628: Swift XRT refined analysis
- GRB 070628: Swift detection of a possible burst
- GRB 070612A: Second Epoch WSRT Radio Observations
- GRB 070621: VLT optical observations
- GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
- GRB070612A: Gemini Spectroscopic Redshift
- GRB 070616: Swift XRT refined circular
- GRB 070612A: Possible WSRT Radio Detection
- Swift XRT observations of the INTEGRAL burst GRB070615: Possible
- GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
- SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
- GRB 070612A: SARA detection of possible OT
- GRB 070610: SARA upper limit
- GRB 070610: Swift-XRT refined analysis
- GRB 070611, Swift-BAT refined analysis
- GRB 070419A, deep LBT photometry and possible supernova detection
- GRB 070529, Swift-BAT refined analysis
- GRB 070521 Milagro GeV/TeV Observations
- GRB 070521: Subaru observations and possible host detection
- GRB 070520A: Subaru Observations
- GRB 070517: Gemini optical imaging
- GRB 070510: Swift detection of a possible burst
- GRB 070508: Multicolor optical observations and possible redshift limit
- GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
- GRB070429B: possible host galaxy detection
- GRB 070429A: Swift XRT refined analysis
- GRB 070429B: ROTSE-III Optical Limits
- GRB 070429B: Swift detection of a short burst
- Trigger 276045: Swift detection of a possible burst
- GRB 070411: TLS data shows plateau, flares
- GRB 070406: Astrometrically Refined XRT Position, Unfading Source
- GRB 070406: Bright galaxy in XRT error circle is a quasar
- Short GRB 070406 - Possible Bright Host Galaxy
- GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
- IPN triangulation of GRB070402
- UVOT observations of GRB070330
- GRB 070311: Optical Brightening
- GRB 070306: possible emission-line redshift
- GRB 070309: variability of the XRT afterglow candidate
- GRB 070311: MDM Optical Follow-up
- GRB 070311: PAIRITEL confirmation of variability of REM candidate
- GRB 070311: REM candidate afterglow
- GRB070309: Swift/XRT possible afterglow detection
- GRB 070125: X-ray light curve analysis
- GRB070227: possible X-ray afterglow detection
- GRB 920925C: optical afterglow candidate
- VLA observation of GRB 070223
- GRB070224: Swift-XRT Refined Analysis
- GRB 070223: Swift-XRT Refined Analysis
- GRB 070223: Liverpool Telescope Possible Afterglow Candidate
- GRB 070125 observations with the GMRT
- GRB 070208: MDM Optical Decay
- GRB070126: Swift-XRT Observation
- GRB 070125: optical observation
- GRB 070129, Swift-BAT refined analysis of a particularly long
- GRB 070126: VLT observations
- GRB070126: Swift-XRT possible detection of an afterglow
- Possible GRB 070126: Swift/UVOT Upper Limit
- GRB070125: Swift-XRT Refined Analysis
- GRB 070126?: Swift detection of a possible burst
- GRB 070110: Continued Detection and Request for Ground Followup
- GRB 070110: Ep,i - Eiso correlation
- Trigger 255685: Swift detection of a possible burst
- GRB 070110: Swift detection of a burst with a possible optical afterglow
- GRB 070107: Possible UVOT Afterglow
- Retractions of previous Swift-BAT triggers
- GRB 061210: Possible Host Galaxy (S2-G2) Keck Spectrum
- GRB 061218: REM prompt observations
- Swift triggers (#251863) on a possible burst
- GRB 061210: MDM Follow-up Observation
- GRB 061210: Swift XRT analysis - Possible counterparts
- GRB 061214(?): ROTSE-III Optical Limits
- GRB 061214(?): Swift detection of a possible burst