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.
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"
32796 results found.
- GRB 000313 - optical transient in the BATSE error box
- GRB000301C - B and R photometry
- GRB000301C - R photometry
- GRB 000307, Optical Observations
- GRB 000307, BVRI Field Photometry
- GRB 000301C: Optical Spectrum and Redshift
- GRB 000301C: Optical Spectrum and Redshift
- GRB 000301C: A Precise Redshift Determination
- GRB 000301C, Optical Observation
- GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
- GRB 000301C: HST/STIS CCD Imaging of the field
- IPN error box for GRB000307
- GRB 000301c: K' observations
- GRB000301C, optical R-band observations
- GRB000301c - R photometry and nearby faint source confirmation
- GRB 000301C, Optical Observation
- GRB 000301c: K' observations
- GRB 000301C Optical Observations
- GRB 000301C: K' Observations
- GRB000301C - Host galaxy not detected in R (?)
- Optical observations of GRB000301c
- GRB000301C optical observations
- GRB 000301c near-IR observations
- GRB 000301C, Optical Color
- GRB000301C, Optical Spectroscopy
- GRB 000301C, UBVRI field photometry
- GRB 000301C, Optical Observation
- GRB000301C 250 GHz detection
- GRB 000301C R-band observation
- GRB 000301C, Optical Observation
- GRB000301C, near-infrared observations (JHK' photometry)
- GRB 000301C: OT confirmed
- GRB000301c optical observations
- GRB 000301A, Radio Observations
- GRB000301C, optical observations
- GRB000301c, near-infrared observations
- GRB000301C
- GRB 000301C : Optical Candidate
- GRB000301C: RXTE/ASM and IPN localizations
- GRB000226 [IPN Position]
- HST Observations of GRB 990712
- GRB 000214 near-IR observations
- GRB 000115 Optical observations
- GRB 000214, Radio Observations
- GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
- GRB 000115, BVRI field photometry
- IPN annulus for GRB000214
- BATSE GRB trigger criterion changed
- GRB000210 X-ray afterglow
- GRB000214: X-ray afterglow candidate
- BeppoSAX GRB000214 ("S. Valentine's day GRB")
- GRB 000210: BATSE Observations
- Optical observations of the Chandra X-ray source for GRB000210
- Chandra Observations of GRB000210 X-ray Afterglow
- IPN triangulation of GRB000210
- GRB 000201: TAROT optical observations
- GRB 000131 Optical Observations
- GRB000126 Optical Observations
- BATSE GRB trigger criteria changed
- GRB 991208, radio observations
- BATSE+IPN location of GRB000131
- IPN localization of GRB000131
- GRB 000126, optical observations
- GRB000126, optical observations
- BATSE location of GRB000126
- IPN localization of GRB000126
- GRB 000115 Optical observations
- BATSE Observations of GRB000115
- Second RXTE Observation of GRB 000115
- GRB991216, UBVRIJHK field photometry
- Single IPN error box for GRB991229
- GCN resumes full operations
- GRB 991216 VLBA Observations
- BEPPOSAX GRBM Localization of GRB991226
- IPN error boxes for GRB991229
- GRB 991216: J band spectrophotometry
- GRB 991216: Detection of the Host and/or Absorber Galaxy
- IPN localization of GRB991226
- Single IPN error box for GRB991221
- IPN error boxes for GRB991221
- GRB 991216 RXTE ASM Observations
- IPN error box for GRB991216
- GRB 991216: Updated BATSE parameters
- Lowell/Perkins observation of GRB 991216
- GRB 991217 (SAX J2303.2+0015) Optical observations
- Chandra observation of the X-ray afterglow of GRB991216
- GRB 991216, optical observations
- GRB 991216 Optical Observations
- GRB 991216 Optical spectroscopy/imaging
- K observations of GRB991216
- GRB 991217 (SAX J2303.2+0015) Optical observations
- GRB991216 Spectroscopy
- Lowell/Perkins observation of GRB 991216
- GRB991216, optical observations
- Refined IPN localization of GRB991216
- GRB 991216 Radio Observations
- GRB 991217
- GRB 991208 Keck Spectroscopy
- GRB 991208 Infrared Detection
- GRB 991216--Summary of RXTE Observations