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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"

26301 results found.

  1. GRB020405: predicted break
  2. GRB 020409, No Optical Detection to R = 22
  3. GRB 020409, 2nd epoch optical observations
  4. GRB 020331 Kyoto observation on March 31
  5. GRB 020409, No Optical Detection to R = 20
  6. X-ray afterglow of GRB020321
  7. GRB020331: Confirmation of Afterglow Candidate with Magellan
  8. GRB020405: VLT optical observations and V band decay slope
  9. GRB020331 optical observations with RIMOTS
  10. GRB020124 optical observations with RIBOTS/RIMOTS
  11. ASM GRB candidate 020406 refined error box
  12. GRB020331: Optical Observations of Afterglow Candidate
  13. GRB020405: VLT optical observations
  14. GRB020405: OT observations
  15. GRB 020331: Candidate Optical Afterglow
  16. GRB 020405: Decay index
  17. GRB020405, Radio Observations
  18. V band observations of GRB020405
  19. GRB 020405, U-band observations
  20. IPN localization of GRB020405
  21. GRB011212: Optical Observations
  22. GRB 020331: NIR Observations
  23. GRB 020331, NIR observations
  24. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  25. GRB 020321: Infrared observations
  26. GRB 020322: BeppoSAX observations of the X-ray afterglow
  27. SN 2002ap - peak brightness date (SN/GRB?)
  28. Near-Infrared Observations of GRB020322 at TIRGO
  29. GRB 020322: Optical Observations
  30. GRB011211 revised BVRI field photometry
  31. GRB020305 BVRI field photometry
  32. GRB020322 BVRI field photometry
  33. GRB 020322 optical observations
  34. GRB020317 : Near IR Observations from Mt Abu Observatory
  35. GRB 020322: Optical Sources and Improved Astrometry
  36. GRB020322, optical observations
  37. XMM-Newton observation of GRB020322
  38. GRB020322: Optical Observations
  39. GRB 020321: Optical observations
  40. GRB020317: optical observations
  41. GRB020321: a faint BeppoSAX detection
  42. GRB020305: NIR observations
  43. GRB 020317 : KISO Optical Observations
  44. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  45. GRB 020305: Optical Observations
  46. GRB020317, optical observations
  47. GRB 011121: Third HST Epoch
  48. GRB020305: Properties of the Candidate Optical Afterglow
  49. GRB 011121: HST Observations reveal an intermediate-time multicolor
  50. GRB011121, possible supernova association
  51. GRB011130 (XRF011130) Second Epoch Chandra Observations
  52. GRB020305: Subaru Optical Observations
  53. GRB020305, optical observations
  54. IPN triangulation of GRB020305 (HETE 1939)
  55. GRB020305 (=H1939): Localization of a GRB by HETE
  56. HST Imaging of the afterglow and host of GRB 011121
  57. GRB 010921: HST Observations
  58. IPN detection and localization of Cygnus X-1 flares
  59. RXTE Observations of SGR 1900+14
  60. SGR1900+14 activity
  61. IPN/HETE Detection of Bursts from SGR1900+14
  62. IPN Upper Limits to a GRB Associated With SN2002ap
  63. GRB020124 BVRI field photometry
  64. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  65. SN2002ap (SN/GRB?) Echelle spectra
  66. GRB020127 Optical Observations
  67. SN 2002ap (SN/GRB?)
  68. SN 2002ap in M74
  69. SN2002ap (SN/GRB?) UBVRI Field Photometry
  70. GRB020127: Chandra Observations and Prospective Counterparts
  71. GRB020124, optical observations
  72. GRB020127: Optical observations
  73. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  74. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  75. GRB 020124 Optical Observations
  76. IPN triangulation of GRB020124 (HETE 1896)
  77. GRB 020124: Optical afterglow
  78. GRB020124(=H1896): Localization of a Long GRB by HETE
  79. Possible optical counterpart to a GRB
  80. GRB011211: BeppoSAX/GRBM data
  81. Optical polarization observations for GRB011211
  82. GRB 011211: Detection of the Probable Host Galaxy
  83. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  84. Color indices of the afterglow of GRB011211
  85. GRB011212: Optical observations at Gunma
  86. GRB 011211, spectrum and optical photometry
  87. GRB 011130: Optical Observations of X-ray and Radio Sources
  88. GRB 011130, Radio/X-ray Comparison
  89. GRB 011211: Evidence for an Optical Break
  90. GRB 011211: TNG Spectroscopic Observations
  91. GRB 011212: optical observation at Oslo (relayed)
  92. GRB 011211, Optical Observations
  93. GRB011211, BVRI field photometry
  94. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  95. Fading of the optical source associated of XRF 011211
  96. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  97. GRB 011130: Optical Observations of Chandra Sources
  98. GRB 011130: Optical Observations of Chandra sources
  99. GRB011130 (XRF011130) Chandra Observations
  100. GRB011130 (=XRF011130): Scheduled Target of Opportunity

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