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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').
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"
  1. GRB 070220: MITSuME Okayama Optical Observation
  2. GRB 070220: ART-3 Optical and NIR limits
  3. GRB 070220 Swift-BAT Refined Analysis
  4. Swift/UVOT refined analysis of GRB070220
  5. GRB 070209: Swift XRT refined analysis
  6. GRB 070220: Swift-XRT Refined Analysis
  7. GRB 070220: Observation with the KANATA 1.5m telescope
  8. GRB 070219: Gemini Observations
  9. GRB 070220 : Faulkes Telescope North optical limit
  10. GRB 070220: Swift detection of a burst
  11. GRB070219: MASTER-VWF-Kislovodsk observations
  12. GRB 070219: XRT Refined Analysis
  13. GRB 070219: Swift/UVOT Upper limits
  14. GRB 070219: I-band observations
  15. GRB 070219, Swift-BAT refined analysis
  16. GRB 070219: optical TNG observations
  17. GRB 070219: Liverpool Telescope Observations
  18. GRB 070219: ROTSE-III Optical Limits
  19. GRB070219 - SDSS Pre-Burst Observations
  20. GRB 070219: Swift detection of a burst
  21. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  22. GRB 070125 observations with the GMRT
  23. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  24. Swift-BAT trigger 260304 is NOT a burst or transient
  25. GRB 060927: PROMPT Observations
  26. GRB 070201: Correction to GCN 6094
  27. GRB 070129: MDM I-band Detection
  28. GRB 070125: Break in Optical Decay
  29. GRB 070209: Swift XRT analysis
  30. GRB 070201: clarification on localization and Konus-Wind spectra
  31. GRB070208: optical observations
  32. GRB 070201: IPN constraints and nearby galaxies
  33. GRB 070201: Proximity of IPN annulus to M31
  34. GRB 070208: MARGE Optical Observations
  35. IPN localization of very bright long hard GRB 070207
  36. IPN localization of very intense short GRB 070201
  37. GRB 070209, Swift-BAT refined analysis of the short hard burst
  38. GRB 070209: Swift detection of a short hard burst
  39. GRB 070208: Swift XRT refined analysis
  40. GRB 070208: RAPTOR detection of early afterglow onset
  41. GRB070208: Absorption and emission redshift from Gemini
  42. GRB 070208: MDM Optical Decay
  43. GRB 070208, Swift-BAT refined analysis
  44. GRB070208 - SDSS Pre-Burst Observations
  45. GRB 070208: Early IR detection and afterglow astrometry
  46. GRB 070208: Afterglow confirmation from P60
  47. GRB070208: Faulkes Telescope North Afterglow Identification
  48. GRB 070208: ROTSE-III Optical Limits
  49. GRB 070208: MDM Observations
  50. GRB 070208: Swift detection of a burst
  51. GRB 070125 detection with CARMA
  52. Swift-BAT trigger 259527 is a Cosmic Ray Shower
  53. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  54. GRB 070129: afterglow confirmation
  55. GRB070124: Swift-XRT Follow-up Observation
  56. GRB070126: Swift-XRT Observation
  57. GRB 070125: further AAVSO optical observations
  58. GRB 070129: Swift/UVOT Upper limits
  59. GRB 070129: dust-scattered X-ray halo detected by Swift/XRT
  60. GRB 070125: optical observation
  61. GRB 070125: WSRT Radio Detection
  62. GRB070129: MITSuME optical observation
  63. Radio detection of GRB 070125
  64. GRB061217: MAGIC telescope GeV observation
  65. GRB 070125: confirmation of pseudo-redshift
  66. GRB 070129, Swift-BAT refined analysis of a particularly long
  67. GRB 070129: Xinglong TNT optical Upper Limit
  68. GRB 070129: Swift-XRT Refined Analysis
  69. GRB 070129: VLT observations
  70. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  71. GRB 070129: Swift detection of a burst
  72. GRB 070126: Swift/UVOT refined analysis
  73. GRB 070125: further AAVSO optical observations
  74. GRB 070125: MITSuME Okayama optical observation
  75. Konus-Wind observation of GRB 070125
  76. GRB 070125: AAVSO optical observations
  77. GRB 070125: optical observations
  78. GRB 070126: VLT observations
  79. GRB070126: Swift-XRT possible detection of an afterglow
  80. GRB 070125: PROMPT detections
  81. GRB 070124: Suzaku WAM observation of the prompt emissions
  82. GRB 070125: WSRT Radio Observations
  83. GRB 070125: UVOT Detection in Ultraviolet Filters
  84. GRB 070126, Swift-BAT refined analysis of a very faint burst
  85. GRB070125: Optical observation by Kanata
  86. GRB070124: Swift-XRT Observation
  87. Possible GRB 070126: Swift/UVOT Upper Limit
  88. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  89. GRB 070125: Xinglong TNT optical observations
  90. GRB 070125: Continued P60 Observations
  91. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  92. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  93. GRB 070125: Lick 3m Spectroscopy
  94. GRB070125: Swift-XRT Refined Analysis
  95. GRB 070125: SARA detection in R
  96. GRB 070125: P60 Optical Afterglow Candidate
  97. GRB 070126?: Swift detection of a possible burst
  98. GRB070125 redshift request
  99. RHESSI Spectrum of GRB070125
  100. IPN-BAT localization of GRB070125 (very long duration, intense)

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