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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 060605 new redshift
  2. GRB 070125, deep late-time optical observation
  3. VLA observation of GRB 070224
  4. GRB 070227: optical observations
  5. GRB 070223: Optical Observations
  6. GRB 070227: optical observations
  7. GRB 070227: Swift/UVOT Upper Limits
  8. GRB 070227: TAROT La Silla observatory optical observations
  9. GRB 070227, Swift-BAT refined analysis
  10. GRB070227: possible X-ray afterglow detection
  11. GRB 070227: Swift detection of a burst in ground analysis
  12. GRB 920925C: optical afterglow candidate
  13. GRB 070224: Optical afterglow confirmation
  14. IBAS Alert n. 4144: not a GRB
  15. GRB 070224: Swift/UVOT Upper Limits
  16. GRB070224: Swift-XRT Astrometrically Corrected Position
  17. VLA observation of GRB 070223
  18. VLA observation of GRB 070220
  19. GRB070224: Magellan Imaging Observations
  20. GRB 070224: WHT K-band imaging
  21. GRB 070224: MDM Observations
  22. GRB070224: Gemini Imaging Observations
  23. GRB 070224: SARA upper limit
  24. GRB070224: Swift-XRT Refined Analysis
  25. GRB 070224: optical afterglow candidate
  26. GRB 070224, Swift-BAT refined analysis
  27. GRB 070224: MASTER-Net refind analysis
  28. GRB 070224: MASTER-VWF-Kislovodsk observations
  29. GRB 070224: MASTER observations
  30. GRB 070224: Swift detection of a burst
  31. GRB 070223: Optical observations
  32. RHESSI Spectrum of GRB070220
  33. GRB070223: Swift/UVOT refined analysis
  34. GRB 070223: Optical-IR observation with KANATA
  35. GRB 070223, Swift-BAT refined analysis
  36. GRB070223: MASTER-VWF-Kislovodsk observations
  37. GRB 070223: Swift-XRT Refined Analysis
  38. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  39. GRB070223 - SDSS Pre-Burst Observations
  40. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  41. GRB 070223: MDM Observations
  42. GRB070223: Swift burst
  43. Konus-Wind and Konus-A observations of GRB 070220
  44. GRB 070220: MITSuME Okayama Optical Observation
  45. GRB 070220: ART-3 Optical and NIR limits
  46. GRB 070220 Swift-BAT Refined Analysis
  47. Swift/UVOT refined analysis of GRB070220
  48. GRB 070209: Swift XRT refined analysis
  49. GRB 070220: Swift-XRT Refined Analysis
  50. GRB 070220: Observation with the KANATA 1.5m telescope
  51. GRB 070219: Gemini Observations
  52. GRB 070220 : Faulkes Telescope North optical limit
  53. GRB 070220: Swift detection of a burst
  54. GRB070219: MASTER-VWF-Kislovodsk observations
  55. GRB 070219: XRT Refined Analysis
  56. GRB 070219: Swift/UVOT Upper limits
  57. GRB 070219: I-band observations
  58. GRB 070219, Swift-BAT refined analysis
  59. GRB 070219: optical TNG observations
  60. GRB 070219: Liverpool Telescope Observations
  61. GRB 070219: ROTSE-III Optical Limits
  62. GRB070219 - SDSS Pre-Burst Observations
  63. GRB 070219: Swift detection of a burst
  64. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  65. GRB 070125 observations with the GMRT
  66. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  67. Swift-BAT trigger 260304 is NOT a burst or transient
  68. GRB 060927: PROMPT Observations
  69. GRB 070201: Correction to GCN 6094
  70. GRB 070129: MDM I-band Detection
  71. GRB 070125: Break in Optical Decay
  72. GRB 070209: Swift XRT analysis
  73. GRB 070201: clarification on localization and Konus-Wind spectra
  74. GRB070208: optical observations
  75. GRB 070201: IPN constraints and nearby galaxies
  76. GRB 070201: Proximity of IPN annulus to M31
  77. GRB 070208: MARGE Optical Observations
  78. IPN localization of very bright long hard GRB 070207
  79. IPN localization of very intense short GRB 070201
  80. GRB 070209, Swift-BAT refined analysis of the short hard burst
  81. GRB 070209: Swift detection of a short hard burst
  82. GRB 070208: Swift XRT refined analysis
  83. GRB 070208: RAPTOR detection of early afterglow onset
  84. GRB070208: Absorption and emission redshift from Gemini
  85. GRB 070208: MDM Optical Decay
  86. GRB 070208, Swift-BAT refined analysis
  87. GRB070208 - SDSS Pre-Burst Observations
  88. GRB 070208: Early IR detection and afterglow astrometry
  89. GRB 070208: Afterglow confirmation from P60
  90. GRB070208: Faulkes Telescope North Afterglow Identification
  91. GRB 070208: ROTSE-III Optical Limits
  92. GRB 070208: MDM Observations
  93. GRB 070208: Swift detection of a burst
  94. GRB 070125 detection with CARMA
  95. Swift-BAT trigger 259527 is a Cosmic Ray Shower
  96. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  97. GRB 070129: afterglow confirmation
  98. GRB070124: Swift-XRT Follow-up Observation
  99. GRB070126: Swift-XRT Observation
  100. GRB 070125: further AAVSO optical observations

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