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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"

19548 results found.

  1. GRB050209: TAROT optical observations
  2. GRB050209: REM optical observations
  3. GRB 050209 I-band observation
  4. GRB 050209 Optical observations
  5. GRB050209: P60 Optical Observations
  6. GRB 050128: Radio observations
  7. Further analysis of the short Swift-BAT GRB 050202
  8. GRB 050202: Short burst detected by Swift-BAT
  9. GRB 050128 Optical observation with REM
  10. GRB 050128: near-infrared observations with REM
  11. GRB050128,optical observations
  12. GRB050126: Updated Swift XRT Position
  13. GRB 050128: Swift XRT prompt afterglow position
  14. GRB 050124: K-band afterglow observations
  15. GRB050126: MASTER optical limit for KECK OT
  16. GRB050126: MASTER optical observations
  17. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  18. GRB 050124 I-band observation
  19. GRB 050124: NIR Candidates from Keck/NIRC
  20. GRB050124,optical observation
  21. GRB050124: Updated Swift XRT Position and Fluxes
  22. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  23. GRB050123: optical limit 1.8h before GRB
  24. GRB050123,optical observation
  25. GRB 050123: KAIT observations
  26. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  27. GRB050117: MASTER optical observations
  28. MASTER:GRB050117 SWIFT
  29. GRB050117: Swift XRT Position
  30. SGR 1806-20: Further low frequency GMRT results
  31. SGR 1806-20: Further VLA Observations
  32. SGR1806-20: Swift-BAT observations of two additional bursts
  33. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  34. SGR 1806-20 and extragalactic short-duration GRBs
  35. SGR 1806-20, RHESSI observations of the 041227 giant flare
  36. GRB 041217: Optical observations
  37. GRB041223: decay of the afterglow
  38. GRB 041224: near-infrared observations with REM
  39. GRB041223: optical and NIR observations with REM
  40. Swift-BAT Time History of GRB041219
  41. GRB 041219: TAROT optical observations
  42. GRB 041218: TAROT optical observations
  43. GRB 041223: J-band observations of the afterglow
  44. GRB 041219c: PROMPT Observations
  45. GRB041223: Swift-BAT detection of a bright long burst
  46. GRB041220: Swift-BAT burst
  47. Deep RAPTOR observations during GRB 041219
  48. GRB 041218 Optical Observations
  49. GRB041219: Continued NIR Observations
  50. GRB 041219 ,optical observation
  51. GRB 041219: Radio Afterglow Detection
  52. GRB 041218 : Radio Observations
  53. GRB 041218: R-band optical observations
  54. GRB041218: optical observations
  55. GRB041219: Confirmed NIR Afterglow
  56. Swift-BAT detection of the bright long burst GRB041219
  57. GRB 041219: Infrared Afterglow Candidate
  58. GRB041219, BVRcIc field calibration
  59. GRB 041219: Infrared Afterglow Candidate
  60. GRB041218, BVRcIc field calibration
  61. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  62. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  63. GRB 041217: PROMPT Observations
  64. GRB041217: NIR and optical observations with REM
  65. GRB041217: Infrared Observations
  66. GRB041217: The First GRB Located On-Board Swift
  67. GRB041211: Faulkes Telescope continued optical monitoring
  68. Optical transient (GRB?) in Lynx
  69. GRB041211: RAPTOR observations
  70. GRB041211: Ashra Prototype optical observation
  71. GRB041211, BVRcIc field calibration
  72. GRB041211,optical observation
  73. GRB 041211: Infrared Observations
  74. GRB 041211: KAIT observations
  75. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  76. GRB 040924: Afterglow Color
  77. GRB 041006: GETS Optical Afterglow Observation
  78. GRB 041006: Optical Observations
  79. GRB041006, late-time optical photometry
  80. GRB041006: RTT150 Optical Observations
  81. GRB 041016: BOOTES-2 simultaneous observation
  82. GRB041006: RTT150 Optical Observations
  83. GRB041016,optical observation
  84. GRB 041016: Optical limits
  85. GRB 041016:Optical limit during first minute
  86. GRB 041016: Optical limit
  87. GRB 041015 R band observations
  88. GRB040924, BVRcIc field calibration
  89. GRB041015,optical observation
  90. GRB041006: Fading X-ray Afterglow Observed with Chandra
  91. GRB 041015 - A long GRB detected by INTEGRAL
  92. GRB041006: Optical observations and Potential host galaxy
  93. GRB041006, BVRcIc field calibration
  94. GRB 041006: SARA afterglow observations
  95. GRB041006, optical observation in CrAO
  96. Search for SN light in XRF 040912 with MEGACAM
  97. GRB 041006: BR observations with VATT
  98. GRB041006, optical I observation
  99. ROTSE-IIIa Observations of GRB 041006
  100. GRB041006: MASTER optical observations

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