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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"

15985 results found.

  1. GRB 050401: Optical afterglow candidate
  2. GRB050331: No Afterglow Detected
  3. GRB 050331: Swift UVOT Source
  4. GRB050319: radio observation
  5. GRB050326: optical limit
  6. GRB 050326: Early observations with Swift-UVOT
  7. GRB050326: optical limit 33min before GRB
  8. GRB050319, optical observations
  9. GRB050319, color indices
  10. GRB050319: optical observation, March 20-22
  11. GRB050319: RTT150 Optical Observations
  12. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  13. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  14. GRB050319: VLA Observations
  15. GRB050319: radio observation
  16. GRB 050319 R band observations
  17. GRB 050319: Swift-UVOT detection of the afterglow
  18. GRB050319: Radio Observations
  19. GRB 050319: NIR afterglow candidate
  20. GRB 050319:Near IR afterglow
  21. GRB050319: BR optical photometry
  22. GRB 050319: Optical observation
  23. GRB 050319 : Confirmation of optical afterglow decay
  24. GRB050319,optical observation
  25. GRB 050319: Detection of Possible Optical Counterpart
  26. GRB 050318: Swift/UVOT detection of afterglow emission
  27. GRB 050318: Magellan optical afterglow identification
  28. GRB 050315, SMARTS optical afterglow decay
  29. GRB050223: analysis of the XMM-Newton observation
  30. GRB050316: MASTER before, simultanious and follow up optical
  31. GRB 050306: ROTSE-III early limits
  32. GRB050316: MASTER optical observations
  33. GRB 050315, SMARTS optical/IR afterglow observations
  34. GRB 050315 I-band observations
  35. GRB050315: Radio afterglow
  36. GRB 050315: Optical afterglow identification
  37. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  38. GRB 050315: Early Observations with Swift/UVOT
  39. GRB050223: No XMM-Newton OM detection of afterglow emission
  40. GRB 050306: Radio Observations
  41. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  42. GRB050309: CONCAM pre-trigger and trigger coincident optical
  43. GRB 050306: optical afterglow
  44. GRB 050309, Early optical limits from RAPTOR
  45. GRB 050306: further TAROT optical data
  46. GRB050309: Early optical limit from P60
  47. Swift 107873: P60 Optical Observations
  48. GRB 050306: CORRECTION to date of observation
  49. GRB 050306: No Swift UVOT Optical Counterpart Detected
  50. GRB 050306: REM optical-infrared observations
  51. Swift trigger 107518: optical observation
  52. GRB 050306: TAROT optical observations
  53. GRB 050306,optical observation
  54. GRB050215B: Late-Time Swift UVOT Observations
  55. GRB 050219b: candidate NIR afterglow
  56. GRB 050223: optical observations
  57. GRB050223: No Swift UVOT Detection of Afterglow Emission
  58. GRB050223: ROTSE-III Optical Observations
  59. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  60. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  61. GRB 050219a: Optical observations from LCO
  62. GRB 050219b: Optical and near-IR observations from LCO
  63. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  64. GRB 050219a, optical observations
  65. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  66. GRB050215b: Swift UVOT Detection of Afterglow Emission
  67. GRB 050215B: Radio Observations
  68. GRB050215b: P60 Optical Observations
  69. GRB 050215b: Swift XRT Source Variability
  70. GRB 050215b, BOOTES-2 simultaneous optical observations
  71. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  72. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  73. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  74. GRB 050215b, BOOTES-1B optical limit
  75. GRB050215B: ROTSE-III optical observations
  76. GRB050215A: ROTSE-III Optical Observations
  77. GRB050209: TAROT optical observations
  78. GRB 050209(=U11568): Duration and spectrum
  79. short/hard GRB 050202, optical observations
  80. GRB050209: REM optical observations
  81. GRB 050209 Optical observations
  82. GRB050209: P60 Optical Observations
  83. GRB050209 (=U11568): A Long GRB Detected by HETE
  84. GRB 050209: Optical observation
  85. GRB 050129: Optical observations
  86. GRB 050202: Optical observations with LCO40
  87. GRB 050128 Optical observation with REM
  88. GRB 050128: near-infrared observations with REM
  89. GRB050128,optical observations
  90. GRB 050128: Swift XRT prompt afterglow position
  91. GRB050126: MASTER optical limit for KECK OT
  92. GRB050126: MASTER optical observations
  93. GRB050124: No Swift UVOT Detection of Afterglow Emission
  94. GRB 050124, SMARTS optical/IR observations
  95. GRB050124,optical observation
  96. GRB050123: optical limit 1.8h before GRB
  97. GRB050123,optical observation
  98. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  99. CFHTLS optical transient unlikely to be a GRB
  100. Unusual optical transient (GRB ???)

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