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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. GRB070224: Gemini Imaging Observations
  2. GRB 070224: SARA upper limit
  3. GRB070224: Swift-XRT Refined Analysis
  4. GRB 070224: optical afterglow candidate
  5. GRB 070224, Swift-BAT refined analysis
  6. GRB 070224: MASTER-Net refind analysis
  7. GRB 070224: MASTER-VWF-Kislovodsk observations
  8. GRB 070224: MASTER observations
  9. GRB 070224: Swift detection of a burst
  10. GRB 070223: Optical observations
  11. RHESSI Spectrum of GRB070220
  12. GRB070223: Swift/UVOT refined analysis
  13. GRB 070223: Optical-IR observation with KANATA
  14. GRB 070223, Swift-BAT refined analysis
  15. GRB070223: MASTER-VWF-Kislovodsk observations
  16. GRB 070223: Swift-XRT Refined Analysis
  17. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  18. GRB070223 - SDSS Pre-Burst Observations
  19. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  20. GRB 070223: MDM Observations
  21. GRB070223: Swift burst
  22. Konus-Wind and Konus-A observations of GRB 070220
  23. GRB 070220: MITSuME Okayama Optical Observation
  24. GRB 070220: ART-3 Optical and NIR limits
  25. GRB 070220 Swift-BAT Refined Analysis
  26. Swift/UVOT refined analysis of GRB070220
  27. GRB 070209: Swift XRT refined analysis
  28. GRB 070220: Swift-XRT Refined Analysis
  29. GRB 070220: Observation with the KANATA 1.5m telescope
  30. GRB 070219: Gemini Observations
  31. GRB 070220 : Faulkes Telescope North optical limit
  32. GRB 070220: Swift detection of a burst
  33. GRB070219: MASTER-VWF-Kislovodsk observations
  34. GRB 070219: XRT Refined Analysis
  35. GRB 070219: Swift/UVOT Upper limits
  36. GRB 070219: I-band observations
  37. GRB 070219, Swift-BAT refined analysis
  38. GRB 070219: optical TNG observations
  39. GRB 070219: Liverpool Telescope Observations
  40. GRB 070219: ROTSE-III Optical Limits
  41. GRB070219 - SDSS Pre-Burst Observations
  42. GRB 070219: Swift detection of a burst
  43. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  44. GRB 070125 observations with the GMRT
  45. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  46. Swift-BAT trigger 260304 is NOT a burst or transient
  47. GRB 060927: PROMPT Observations
  48. GRB 070201: Correction to GCN 6094
  49. GRB 070129: MDM I-band Detection
  50. GRB 070125: Break in Optical Decay
  51. GRB 070209: Swift XRT analysis
  52. GRB 070201: clarification on localization and Konus-Wind spectra
  53. GRB070208: optical observations
  54. GRB 070201: IPN constraints and nearby galaxies
  55. GRB 070201: Proximity of IPN annulus to M31
  56. GRB 070208: MARGE Optical Observations
  57. IPN localization of very bright long hard GRB 070207
  58. IPN localization of very intense short GRB 070201
  59. GRB 070209, Swift-BAT refined analysis of the short hard burst
  60. GRB 070209: Swift detection of a short hard burst
  61. GRB 070208: Swift XRT refined analysis
  62. GRB 070208: RAPTOR detection of early afterglow onset
  63. GRB070208: Absorption and emission redshift from Gemini
  64. GRB 070208: MDM Optical Decay
  65. GRB 070208, Swift-BAT refined analysis
  66. GRB070208 - SDSS Pre-Burst Observations
  67. GRB 070208: Early IR detection and afterglow astrometry
  68. GRB 070208: Afterglow confirmation from P60
  69. GRB070208: Faulkes Telescope North Afterglow Identification
  70. GRB 070208: ROTSE-III Optical Limits
  71. GRB 070208: MDM Observations
  72. GRB 070208: Swift detection of a burst
  73. GRB 070125 detection with CARMA
  74. Swift-BAT trigger 259527 is a Cosmic Ray Shower
  75. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  76. GRB 070129: afterglow confirmation
  77. GRB070124: Swift-XRT Follow-up Observation
  78. GRB070126: Swift-XRT Observation
  79. GRB 070125: further AAVSO optical observations
  80. GRB 070129: Swift/UVOT Upper limits
  81. GRB 070129: dust-scattered X-ray halo detected by Swift/XRT
  82. GRB 070125: optical observation
  83. GRB 070125: WSRT Radio Detection
  84. GRB070129: MITSuME optical observation
  85. Radio detection of GRB 070125
  86. GRB061217: MAGIC telescope GeV observation
  87. GRB 070125: confirmation of pseudo-redshift
  88. GRB 070129, Swift-BAT refined analysis of a particularly long
  89. GRB 070129: Xinglong TNT optical Upper Limit
  90. GRB 070129: Swift-XRT Refined Analysis
  91. GRB 070129: VLT observations
  92. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  93. GRB 070129: Swift detection of a burst
  94. GRB 070126: Swift/UVOT refined analysis
  95. GRB 070125: further AAVSO optical observations
  96. GRB 070125: MITSuME Okayama optical observation
  97. Konus-Wind observation of GRB 070125
  98. GRB 070125: AAVSO optical observations
  99. GRB 070125: optical observations
  100. GRB 070126: VLT observations

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