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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"

26009 results found.

  1. GRB 020331 Kyoto observation on March 31
  2. GRB020410: BeppoSAX NFI observation
  3. X-ray afterglow of GRB020321
  4. GRB020331 optical observations with RIMOTS
  5. GRB020124 optical observations with RIBOTS/RIMOTS
  6. GRB 020321: Candidate X-ray Counterparts
  7. GRB020406(?), optical observations
  8. GRB 020405: Decay index
  9. Short RXTE/ASM transient 020406; may be a GRB
  10. GRB020405, Radio Observations
  11. GRB 020405, U-band observations
  12. GRB011212: Optical Observations
  13. GRB 020331: NIR Observations
  14. GRB020331 NIR observation at KPNO (re-submission)
  15. GRB02033 NIR observation at KPNO
  16. GRB020331 field photometry
  17. GRB 020331, NIR observations
  18. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  19. GRB 020322: BeppoSAX observations of the X-ray afterglow
  20. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  21. Near-Infrared Observations of GRB020322 at TIRGO
  22. GRB 020321, Radio Observations
  23. GRB 020322: Optical Observations
  24. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  25. GRB 020321: Optical observations
  26. GRB020317 BVRI field photometry
  27. GRB011211 revised BVRI field photometry
  28. GRB020305 BVRI field photometry
  29. GRB020322 BVRI field photometry
  30. GRB 020322: Optical Sources and Improved Astrometry
  31. GRB020317: optical observations
  32. GRB020321 optical observations
  33. GRB020321: a faint BeppoSAX detection
  34. GRB 020317 : KISO Optical Observations
  35. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  36. GRB 020305: Optical Observations
  37. GRB020317, optical observations
  38. GRB 020317: Optical observations
  39. GRB 011121: Third HST Epoch
  40. GRB020305: Properties of the Candidate Optical Afterglow
  41. GRB 011121: HST Observations reveal an intermediate-time multicolor
  42. GRB011130 (XRF011130) Second Epoch Chandra Observations
  43. GRB020305: Subaru Optical Observations
  44. XRF/GRB 011030: Detection of the Probable Host Galaxy
  45. GRB 020305: Candidate optical afterglow
  46. GRB020305, optical observations
  47. IPN triangulation of GRB020305 (HETE 1939)
  48. GRB020305 (=H1939): Localization of a GRB by HETE
  49. HST Imaging of the afterglow and host of GRB 011121
  50. IPN detection and localization of Cygnus X-1 flares
  51. SGR1900+14 activity
  52. IPN Upper Limits to a GRB Associated With SN2002ap
  53. GRB020124 BVRI field photometry
  54. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  55. SN2002ap (SN/GRB?) Echelle spectra
  56. GRB020127 Optical Observations
  57. SN 2002ap in M74
  58. SN2002ap (SN/GRB?) UBVRI Field Photometry
  59. GRB020127: Chandra Observations and Prospective Counterparts
  60. pre-SN2002ap (SN/GRB?) imaging of M74
  61. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  62. GRB020124, optical observations
  63. GRB 020127, I-band observations starting 3.14-hr after the event
  64. GRB010921 Optical Observations
  65. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  66. GRB020124: Optical observations
  67. GRB 020124: Optical observations
  68. GRB 020124: Optical afterglow
  69. GRB020124(=H1896): Localization of a Long GRB by HETE
  70. Possible optical counterpart to a GRB
  71. GRB011212, Optical Observations
  72. Optical polarization observations for GRB011211
  73. GRB 011211: Detection of the Probable Host Galaxy
  74. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  75. GRB 011130: Optical Observations of X-ray and Radio Sources
  76. GRB 011212: optical observation at Asiago
  77. GRB 011211: Evidence for an Optical Break
  78. GRB 011211: TNG Spectroscopic Observations
  79. optical follow-up of GRB(XRF) 011211
  80. GRB 011212: optical observation at Oslo (relayed)
  81. GRB 011211, Optical Observations
  82. GRB011212, BVRI field photometry
  83. GRB011211, BVRI field photometry
  84. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  85. Fading of the optical source associated of XRF 011211
  86. GRB 011211 Optical Observations: Likely Afterglow
  87. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  88. GRB011130 (XRF011130) Chandra Observations
  89. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  90. GRB 011130, K band observations
  91. GRB011130, optical observations
  92. GRB011130 (=XRF011130): Second Revised Localization by HETE
  93. GRB011130 (XRF011130) SDSS PT i-band observations
  94. XRF011130: Infrared Observations
  95. GRB 011121
  96. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  97. GRB 011121: J-band observations
  98. GRB 011121: NIR observations, host galaxy?
  99. GRB011121: UBRI Observations
  100. GRB 011121 J-Band Astrometry

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