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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"

25807 results found.

  1. GRB 080130(?): Swift XRT observation
  2. GRB 080129: Swift-XRT refined analysis
  3. X-ray transient in NGC 2770: RTT150 optical observations
  4. GRB 080129: KAIT optical limits
  5. GRB 080123: Early afterglow detection with BATSS (BAT Slew Survey)
  6. GRB 080129: TAROT La Silla observatory optical observations
  7. GRB 080129: GROND detection in all bands, and fading
  8. GRB 080129: GROND detection of the optical/NIR afterglow, and fading
  9. GRB 080129: Enhanced Swift-XRT position
  10. GRB 080129: Gemini-South Imaging Observations
  11. GRB 080129 (?): UVOT Upper Limits
  12. A new website of high-level data products for Swift GRBs
  13. GRB 080121: Upper limit on X-ray afterglow
  14. GRB 080123 : Suzaku WAM observation of the prompt emission
  15. Konus-Wind observation of GRB 080122
  16. GRB 080122 : Suzaku WAM observation of the prompt emission
  17. GRB 080121: Swift/UVOT upper limits
  18. SNe 2008D and 2007uy: Chandra Detections
  19. GRB 080121: Enhanced Swift-XRT position
  20. Transient 080109/SN 2008D: Spectroscopic Evolution and Re-Classification
  21. IPN triangulation of GRB080122
  22. GRB 080121: Nearby SDSS galaxies
  23. GRB 080121: Swift-BAT detection of a very weak, short burst
  24. GRB 080123: Swift-XRT refined analysis
  25. GRB 080123: Swift/UVOT refined analysis
  26. GRB 080123: Enhanced Swift-XRT position
  27. GRB 080123: Swift detection of a short burst
  28. GRB 080120: GROND confirmation of the optical afterglow
  29. VLA radio upper limit on GRB 080120
  30. GRB 080120: Swift-XRT refined analysis
  31. GRB080120: Swift XRT position
  32. GRB 080120: a long GRB detected by INTEGRAL
  33. Transient XRF 080109 / SN 2008D: Mount Abu NIR observations
  34. XRF 080109 / SN 2008D: UKIRT JHK imaging
  35. optical observations, XRT in NGC 2770
  36. Gemini-South observations of XRF 080109 / SN 2008D
  37. Swift observations of the X-ray transient in NGC 2770 (aka SN2008D)
  38. Discovery of Radio Emission from Transient in NGC 2770
  39. XRF 080109 in NGC2770: NIR observations at TNG
  40. XRB 080109/SN 2008D: Early decline in brightness and change in colors
  41. XRB 080109/SN 2008D:PAIRITEL NIR observations and t_0 from Swift
  42. XRF 080109 in NGC2770: Detectable Superluminal Motion
  43. Refined Swift-XRT analysis of the transient in NGC 2770
  44. Early OT detection of XRF in NGC 2770 in Asiago frames
  45. Bright X-ray Transient (a XRF? ) in NGC 2770 - A SN optical counterpart?
  46. Bright X-ray Transient in NGC 2770 - A low-luminosity XRF?
  47. GRB 071227: Suzaku WAM observation of the prompt emission
  48. GRB 071227: optical afterglow
  49. Further Swift-BAT analysis of GRB 071227
  50. Konus-Wind observation of GRB 071227
  51. GRB 071227: Magellan redshift confirmation
  52. GRB 071227: Swift-XRT refined analysis
  53. GRB 071227: VLT probable redshift of the candidate host galaxy
  54. GRB071227: Swift/UVOT refined analysis
  55. GRB 071227: REM NIR and Optical observations
  56. Swift-BAT refined analysis of short GRB 071227
  57. GRB 071227: Swift detection of a burst
  58. GRB 070429B: Possible UVOT Detection of an Optical Afterglow
  59. GRB 071125: Suzaku WAM observation of the prompt emission
  60. GRB 070429B: Probable host galaxy and redshift
  61. GRB 071129, Swift-BAT refined analysis
  62. GRB 071126: Enhanced Swift-XRT position
  63. GRB071122: Swift/UVOT Observations
  64. GRB071104: NIR Afterglow Candidate at TNG
  65. GRB 071122 Swift-XRT refined analysis
  66. GRB 071122: P60 Optical Afterglow Candidate
  67. GRB 071122: Swift detection of a burst
  68. GRB 071118: P60 Observations
  69. GRB071118 MITSuME OAO optical observation
  70. GRB 071118: Observations from OSN
  71. GRB 071117: VLT observations and probable redshift
  72. Swift/UVOT observations of GRB071118
  73. Konus-Wind and Konus-A observations of GRB 071117
  74. Swift XRT follow-up observations of GRB071008
  75. Swift/UVOT upper limits for GRB 071117
  76. GRB071118: Swift XRT refined analysis
  77. GRB 071117: Gemini Optical Afterglow Discovery
  78. GRB 071118, Swift-BAT refined analysis
  79. GRB 071117: TAROT La Silla observatory optical observations
  80. GRB 071118: Swift detection of a burst
  81. GRB 071117: Gemini Observations
  82. GRB 071117: Swift-XRT refined analysis
  83. Swift detection of MXB 0656-072
  84. GRB 071112C: Optical and NIR data observed with KANATA
  85. GRB 071112C MITSuME Akeno early optical observation
  86. GRB 071112C: SARA upper limit
  87. GRB 071112C : Second Epoch Lulin R-band observations
  88. GRB071112C MITSuME Okayama Optical Observation
  89. GRB 071112C: Swift-BAT refined analysis
  90. GRB 071112C: Swift XRT refined analysis
  91. Swift UVOT upper limits of GRB071112B
  92. GRB 071112C: VLT redshift
  93. GRB 071112B: Gemini Optical Imaging
  94. GRB 071112B: Swift-XRT preliminary analysis
  95. GRB 071112C : Lulin R-band observation
  96. GRB 071112C: TAROT Calern observatory optical observations
  97. Swift XRT follow-up observations of GRB071028B
  98. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  99. GRB 071112C: Optical and NIR afterglows observed with KANATA
  100. GRB 071112C: Swift detection of a burst with an optical counterpart

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