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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"

27393 results found.

  1. GRB 020331, NIR observations
  2. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  3. GRB 020322: BeppoSAX observations of the X-ray afterglow
  4. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  5. Near-Infrared Observations of GRB020322 at TIRGO
  6. GRB 020321, Radio Observations
  7. GRB 020322: Optical Observations
  8. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  9. GRB 020321: Optical observations
  10. GRB020317 BVRI field photometry
  11. GRB011211 revised BVRI field photometry
  12. GRB020305 BVRI field photometry
  13. GRB020322 BVRI field photometry
  14. GRB 020322: Optical Sources and Improved Astrometry
  15. GRB020317: optical observations
  16. GRB020321 optical observations
  17. GRB020321: a faint BeppoSAX detection
  18. GRB 020317 : KISO Optical Observations
  19. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  20. GRB 020305: Optical Observations
  21. GRB020317, optical observations
  22. GRB 020317: Optical observations
  23. GRB 011121: Third HST Epoch
  24. GRB020305: Properties of the Candidate Optical Afterglow
  25. GRB 011121: HST Observations reveal an intermediate-time multicolor
  26. GRB011130 (XRF011130) Second Epoch Chandra Observations
  27. GRB020305: Subaru Optical Observations
  28. XRF/GRB 011030: Detection of the Probable Host Galaxy
  29. GRB 020305: Candidate optical afterglow
  30. GRB020305, optical observations
  31. IPN triangulation of GRB020305 (HETE 1939)
  32. GRB020305 (=H1939): Localization of a GRB by HETE
  33. HST Imaging of the afterglow and host of GRB 011121
  34. IPN detection and localization of Cygnus X-1 flares
  35. SGR1900+14 activity
  36. IPN Upper Limits to a GRB Associated With SN2002ap
  37. GRB020124 BVRI field photometry
  38. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  39. SN2002ap (SN/GRB?) Echelle spectra
  40. GRB020127 Optical Observations
  41. SN 2002ap in M74
  42. SN2002ap (SN/GRB?) UBVRI Field Photometry
  43. GRB020127: Chandra Observations and Prospective Counterparts
  44. pre-SN2002ap (SN/GRB?) imaging of M74
  45. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  46. GRB020124, optical observations
  47. GRB 020127, I-band observations starting 3.14-hr after the event
  48. GRB010921 Optical Observations
  49. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  50. GRB020124: Optical observations
  51. GRB 020124: Optical observations
  52. GRB 020124: Optical afterglow
  53. GRB020124(=H1896): Localization of a Long GRB by HETE
  54. Possible optical counterpart to a GRB
  55. GRB011212, Optical Observations
  56. Optical polarization observations for GRB011211
  57. GRB 011211: Detection of the Probable Host Galaxy
  58. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  59. GRB 011130: Optical Observations of X-ray and Radio Sources
  60. GRB 011212: optical observation at Asiago
  61. GRB 011211: Evidence for an Optical Break
  62. GRB 011211: TNG Spectroscopic Observations
  63. optical follow-up of GRB(XRF) 011211
  64. GRB 011212: optical observation at Oslo (relayed)
  65. GRB 011211, Optical Observations
  66. GRB011212, BVRI field photometry
  67. GRB011211, BVRI field photometry
  68. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  69. Fading of the optical source associated of XRF 011211
  70. GRB 011211 Optical Observations: Likely Afterglow
  71. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  72. GRB011130 (XRF011130) Chandra Observations
  73. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  74. GRB 011130, K band observations
  75. GRB011130, optical observations
  76. GRB011130 (=XRF011130): Second Revised Localization by HETE
  77. GRB011130 (XRF011130) SDSS PT i-band observations
  78. XRF011130: Infrared Observations
  79. GRB 011121
  80. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  81. GRB 011121: J-band observations
  82. GRB 011121: NIR observations, host galaxy?
  83. GRB011121: UBRI Observations
  84. GRB 011121 J-Band Astrometry
  85. GRB 011121: Detection of Bright IR Counterpart
  86. GRB011121: possible redshift, continued decay
  87. GRB 011030: TNG K-band observation
  88. XRF011030: J and K band observations
  89. XRF011030: Chandra Observations
  90. GRB011030: Z-band observations
  91. GRB 011030 R band observations
  92. GRB 011030 I-band Observation
  93. The X-ray Flash 011030 ('GRB 011030')
  94. Non-triggered burst 011030 ("GRB 011030")
  95. The Radio Afterglow from the X-ray Rich GRB 011030
  96. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  97. GRB 970828: HST Observations of the Host Galaxy
  98. GRB 000131: HST Detection of the Host Galaxy
  99. GRB 970828: HST Observations of the Host Galaxy
  100. Optical observation of SGR 1806-20 at the 6-m SAO telescope

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