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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"

2626 results found.

  1. XRF 080109 / SN 2008D: GMRT radio observation at 1280 MHz
  2. XRB 080109/SN 2008D: Early decline in brightness and change in colors
  3. Bright X-ray transient / possible XRF in NGC 2770: TNG R imaging
  4. Possible XRF in NGC 2770 - NOT observations of the optical counterpart
  5. Further Swift-BAT analysis of GRB 071227
  6. GRB 071227: Swift-XRT refined analysis
  7. GRB 070429B: Possible UVOT Detection of an Optical Afterglow
  8. GRB 071208?: Swift detection of a possible burst
  9. GRB 071129, Swift-BAT refined analysis
  10. Disregard the "GRB 071126" position
  11. GRB 071118, Swift-BAT refined analysis
  12. GRB 071112: Swift detection of a possible burst
  13. Swift/UVOT initial analysis of GRB071109
  14. GRB 071109: further Swift-XRT analysis
  15. GRB 071109: Swift-XRT possible X-ray counterpart
  16. GRB 071104: Swift-XRT Team Refined Analysis
  17. GRB 071104: Possible Swift UVOT Afterglow Candidate
  18. GRB 071028: Swift detection of a burst
  19. GRB 071025: ROTSE-III Refined Analysis
  20. Possible radio detection of GRB 071021 with the VLA
  21. GRB 071021: possible high-z burst
  22. GRB071018: Correction to the title of the GCN 6936
  23. GRB 071018: Possible OT from Xinglong TNT observation
  24. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  25. GRB 071018, Swift-BAT refined analysis
  26. GRB 071018?: Swift detection of a possible burst
  27. GRB 071013: 3rd TLS Epoch - constraints on variability
  28. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  29. GRB 071010B possible optical transient
  30. GRB 070810B: further XRT analysis
  31. GRB 071003: Keck spectroscopy
  32. GRB 071003: Possible rebrightening
  33. GRB 071003: Keck HIRES spectroscopy
  34. GRB 071003: MARGE Observations
  35. GRB070925: Swift-XRT Afterglow confirmation
  36. GRB 070917: Confirmation of the X-ray afterglow
  37. Swift Status and XRT Calibration Uncertainties
  38. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  39. Observations of possible TAROT GRB transient near IC 4779
  40. Las Campanas observations of possible TAROT GRB transient near IC
  41. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  42. Swift observatory off line
  43. GRB 070810A: Continued Keck Imaging
  44. GRB 070810B: Keck spectroscopy of possible host galaxies
  45. GRB 070810B: XRT refined analysis
  46. GRB070810B: Optical observations with KANATA
  47. GRB 070810B: Swift detection of a short burst
  48. GRB 070809: Keck Imaging
  49. GRB 070810: Swift detection of a burst
  50. GCN Swift XRT update position notices and enhanced position circulars
  51. GRB070612A: Radio upper limit from GMRT
  52. GRB 070729: LCO optical imaging
  53. Four radio sources in Swift-XRT error box of GRB 070724
  54. GRB 070721: Swift detection of a possible burst
  55. Swift detection of a possible burst (Trigger 284850)
  56. GRB 070611: VLT observations
  57. GRB 070628: Swift XRT refined analysis
  58. GRB 070628: Swift detection of a possible burst
  59. GRB 070612A: Second Epoch WSRT Radio Observations
  60. GRB 070621: VLT optical observations
  61. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  62. GRB070612A: Gemini Spectroscopic Redshift
  63. GRB 070616: Swift XRT refined circular
  64. GRB 070612A: Possible WSRT Radio Detection
  65. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  66. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  67. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  68. GRB 070612A: SARA detection of possible OT
  69. GRB 070610: SARA upper limit
  70. GRB 070610: Swift-XRT refined analysis
  71. GRB 070611, Swift-BAT refined analysis
  72. GRB 070419A, deep LBT photometry and possible supernova detection
  73. GRB 070529, Swift-BAT refined analysis
  74. GRB 070521 Milagro GeV/TeV Observations
  75. GRB 070521: Subaru observations and possible host detection
  76. GRB 070520A: Subaru Observations
  77. GRB 070517: Gemini optical imaging
  78. GRB 070510: Swift detection of a possible burst
  79. GRB 070508: Multicolor optical observations and possible redshift limit
  80. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  81. GRB070429B: possible host galaxy detection
  82. GRB 070429A: Swift XRT refined analysis
  83. GRB 070429B: ROTSE-III Optical Limits
  84. GRB 070429B: Swift detection of a short burst
  85. Trigger 276045: Swift detection of a possible burst
  86. GRB 070411: TLS data shows plateau, flares
  87. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  88. GRB 070406: Bright galaxy in XRT error circle is a quasar
  89. Short GRB 070406 - Possible Bright Host Galaxy
  90. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  91. IPN triangulation of GRB070402
  92. UVOT observations of GRB070330
  93. GRB 070311: Optical Brightening
  94. GRB 070306: possible emission-line redshift
  95. GRB 070309: variability of the XRT afterglow candidate
  96. GRB 070311: MDM Optical Follow-up
  97. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  98. GRB 070311: REM candidate afterglow
  99. GRB070309: Swift/XRT possible afterglow detection
  100. GRB 070125: X-ray light curve analysis

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