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

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