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"5513 results found.
- GRB 071010: Swift detection of a burst
- Recent SGR1806-20 Activity
- GRB 070923: Swift detection of a short hard burst
- GRB920925C: search for host galaxy
- Candidate Orphan GRB Optical Transient in IC 4779
- GRB 070810A: ROTSE-III Refined Analysis
- Swift trigger on 4U 1700-377 while star tracker loss-of-lock
- GRB 070729: Swift-XRT refined analysis
- GRB 070729: Magellan NIR Observations
- GRB 070729: Swift detection of a short hard burst
- GRB 070724B: Swift-XRT afterglow likely candidate
- GRB 070724B: Swift-XRT afterglow candidates
- GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
- GRB 070714B: Keck observations
- GRB 070714A: Swift-BAT T_zero
- GRB 070714A: Swift/UVOT Upper limits
- GRB 070714A: Swift XRT refined analysis
- GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
- GRB 070714 ("Bastille"): Optical Pre-Imaging
- GRB 070714 : Liverpool Telescope optical counterpart ?
- Swift detection of a possible burst (Trigger 284850)
- GRB 070628 Swift-UVOT Refined Analysis
- GRB070616: Optical Observation by MITSuME Akeno
- GRB 070616, Swift-BAT partial refined analysis
- SWIFT J195509.6+261406 (GRB 070610): further observations
- GRB 070612A: Super-LOTIS observations
- GRB 070612A: MDM Observations
- GRB 070517: Gemini optical imaging
- GRB 070509: ROTSE-III Optical Limits
- GRB 070429B: ROTSE-III Optical Limits
- GRB 070429B: Swift detection of a short burst
- LT monitoring of GRB070412
- GRB 070411 : Planned XMM-Newton observation
- GRB 070318, SMARTS optical/IR afterglow observations
- GRB 070411: TLS data shows plateau, flares
- GRB 070411: Swift/UVOT observations
- GRB 070411: Swift-XRT refined analysis
- GRB 070412: Optical observations at Crni Vrh
- GRB 070412: IAC80 optical afterglow candidate
- GRB 070412: Swift detection of a burst
- GRB 070411: Optical observations at Crni Vrh
- GRB 070411: Swift detection of a burst with optical afterglow
- GRB 070406: Swift XRT team further analysis
- GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
- GRB 070328: Suzaku WAM observation of the prompt emission
- GRB 070330, SMARTS optical/IR observations
- GRB 070330: TAROT La Silla observatory optical observations
- Konus-Wind observation of GRB 070328
- GRB 070328: Swift detection of a burst
- GRB 070311, deep optical photometry
- Short-Hard GRB 070209: PROMPT Observations
- GRB 070318: Swift detection of a burst with an optical afterglow
- GRB 070311: Optical Brightening
- GRB 070311: MDM Optical Follow-up
- GRB 070311: MDM Optical Detection
- GRB 070311: MITSuME Okayama Optical Observation
- GRB 070311: Swift-XRT refined analysis
- GRB 070311: PAIRITEL confirmation of variability of REM candidate
- GRB 070311: REM candidate afterglow
- GRB 070309: A long GRB detected by INTEGRAL
- GRB 920925C: optical afterglow candidate
- GRB 070220: ART-3 Optical and NIR limits
- GRB 070219: ROTSE-III Optical Limits
- GRB 070209: Swift XRT analysis
- IPN localization of very bright long hard GRB 070207
- GRB 070209: Swift detection of a short hard burst
- GRB070124: Swift-XRT Follow-up Observation
- GRB070126: Swift-XRT Observation
- GRB 070125: MITSuME Okayama optical observation
- GRB070124: Swift-XRT Observation
- GRB 070110: VLT R-band photometry
- Further Retractions of previous Swift-BAT triggers
- Retractions of previous Swift-BAT triggers
- Konus-Wind observation of GRB 061222A
- GRB 061222A: Prompt ROTSE-III Optical Limits
- GRB 061222: Swift detection of a burst
- GRB 061218: TORTOREM optical upper limits
- GRB 061217: REM prompt observations
- GRB 061217: ROTSE-III Optical Limits
- GRB 061217: Swift detection of a short hard burst
- GRB 061210: MDM Follow-up Observation
- Swift-BAT triggers 238544 and 238546 are not GRBs
- GRB 061102: Swift detection of a burst
- GRB 061025: Gemini-S observations
- GRB061007: Swift UVOT followup observations
- GRB 061007: Magellan Spectroscopy
- GRB 061007: Swift XRT refined analysis
- GRB 061007 - FTS early brightening and power law decay
- GRB 061007: Swift detection of a burst with an optical counterpart
- GRB 061007: ROTSE-III Detection of Optical Counterpart
- IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
- GRB 061002: Swift detection of a burst: CORRECTED CONTENT
- GRB 061002: Swift detection of a burst
- GRB 060923C: VLT J-band observations
- GRB 060923C: Keck Observations
- GRB 060912A: Probable Host Galaxy
- GRB060904b optical detections (delayed report due to internet outage)
- GRB 060904B: RTT150 optical observations
- GRB 060904B: Optical observations at Crni Vrh
- GRB 060904B BOOTES-IR and 1.5m OSN observations