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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

24994 results found.

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

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