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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"

7293 results found.

  1. GRB 050421: NIR observations
  2. GRB 050416b: Tentative Swift XRT Position
  3. GRB050416: P200 NIR Observations
  4. GRB 050416: Swift XRT Position
  5. GRB 050416: Radio observations
  6. GRB050416: P60 Afterglow Candidate
  7. GRB 050412 : XingLong optical observation
  8. GRB 050408: Subaru Observations
  9. GRB 050408 Optical Observations
  10. GRB 050408: Magellan astrometry and photometry
  11. GRB 050408: First Optical observations with TFOSC at the RTT150
  12. GRB 050408 optical candidate
  13. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  14. GRB 050401 Optical Observations
  15. GRB050402: XDSS counterpart
  16. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  17. GRB 050401: Optical afterglow confirmed
  18. GRB 050401: Optical afterglow candidate
  19. GRB 050319 R band observations
  20. GRB 050319: NIR afterglow candidate
  21. GRB 050319:Near IR afterglow
  22. GRB050319: BR optical photometry
  23. GRB 050319 : Confirmation of optical afterglow decay
  24. GRB 050315, SMARTS optical afterglow decay
  25. GRB050316: MASTER optical observations
  26. GRB 050315, SMARTS optical/IR afterglow observations
  27. GRB 050315: Absorption redshift
  28. GRB 050306: Radio Observations
  29. GRB 050306: Confirmation of X-ray afterglow
  30. GRB 050309, Early optical limits from RAPTOR
  31. GRB 050306: CORRECTION to date of observation
  32. GRB 050306: R-band observations
  33. GRB 050306: No Swift UVOT Optical Counterpart Detected
  34. GRB 050306: REM optical-infrared observations
  35. GRB 050306: Possible X-ray Afterglow Position from the Swift
  36. GRB 050126: Confirmation of the NIR afterglow candidate
  37. GRB 050219b: candidate NIR afterglow
  38. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  39. GRB 050215B: Radio Observations
  40. GRB 050215b: XRT confirmation of IR afterglow candidate
  41. GRB050215b: P60 Optical Observations
  42. GRB 050215b: Swift XRT Source Variability
  43. GRB 050215B: candidate afterglow
  44. GRB 050124: Radio Observations
  45. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  46. GRB 050126: Radio Observations
  47. GRB 050128: Swift XRT prompt afterglow position
  48. GRB 050123 : I-band follow-up observation
  49. GRB041223: decay of the afterglow
  50. GRB041223: optical and NIR observations with REM
  51. GRB 041219 : optical follow-up observations
  52. Deep RAPTOR observations during GRB 041219
  53. GRB041218: Continued P60 Optical Observations
  54. GRB 041219: Infrared Afterglow Candidate
  55. GRB 041219: Infrared Afterglow Candidate
  56. GRB 041217: PROMPT Observations
  57. GRB041218: optical observations
  58. GRB 041218; optical candidate
  59. GRB 041218: Optical observations
  60. GRB041211, Faulkes Telescope optical observation
  61. GRB041006: Fading X-ray Afterglow Observed with Chandra
  62. GRB 041006 : Optical follow-up observation at TAROT
  63. GRB041006: Fading of optical afterglow candidate
  64. GRB 041006 : Optical follow-up observation at KISO
  65. GRB 041006: Finding chart
  66. GRB 041006: Optical afterglow candidate
  67. radio observations, GRB 040924
  68. GRB040924,optical observation
  69. GRB 040924: detection of possible host galaxy by Subaru
  70. GRB040924, RTT150 optical observation
  71. GRB040924: Afterglow magnitude at t=17.5hr
  72. GRB040924 : Optical candidate observations at Lulin observatory
  73. GRB040924 : Optical candidate observations at Lulin observatory
  74. GRB 040924: Subaru NIR observation
  75. GRB040924: Optical afterglow properties
  76. IPN triangulation of GRB040924 (H3564)
  77. GRB040924 (H3564): Optical afterglow candidate
  78. XRF 040912: Radio Observations
  79. XRF 040916: Radio Observations
  80. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  81. XRF040916: continuing decay of OT
  82. TAROT Observations of GRB 040916 (HETE #3558)
  83. GRB040912(=H3557): Candidate Optical Afterglow
  84. XRF040916, optical observations
  85. XRF040916: Optical Transient Candidate by Subaru
  86. XRF040916, Ic observations
  87. XRF040916: optical follow-up observations
  88. GRB040916: Archival optical observations
  89. GRB040916: Optical observations
  90. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  91. GRB 040912, BVRI observations
  92. HETE 3557: Optical observations
  93. GRB 040827 - Radio Observations
  94. GRB040825A: Optical observations
  95. GRB040825A: Optical observations
  96. GRB 040825: Optical observations
  97. XRF040812: possible afterglow second Chandra observation
  98. GRB 040812: Second epoch CXO Observations
  99. XRF040701: Second-Epoch Chandra Observations
  100. XRF 040701, optical observations

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