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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"

26272 results found.

  1. GRB 020317: Optical observations
  2. GRB 011121: Third HST Epoch
  3. GRB020305: Properties of the Candidate Optical Afterglow
  4. GRB 011121: HST Observations reveal an intermediate-time multicolor
  5. GRB011130 (XRF011130) Second Epoch Chandra Observations
  6. GRB020305: Subaru Optical Observations
  7. XRF/GRB 011030: Detection of the Probable Host Galaxy
  8. GRB 020305: Candidate optical afterglow
  9. GRB020305, optical observations
  10. IPN triangulation of GRB020305 (HETE 1939)
  11. GRB020305 (=H1939): Localization of a GRB by HETE
  12. HST Imaging of the afterglow and host of GRB 011121
  13. IPN detection and localization of Cygnus X-1 flares
  14. SGR1900+14 activity
  15. IPN Upper Limits to a GRB Associated With SN2002ap
  16. GRB020124 BVRI field photometry
  17. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  18. SN2002ap (SN/GRB?) Echelle spectra
  19. GRB020127 Optical Observations
  20. SN 2002ap in M74
  21. SN2002ap (SN/GRB?) UBVRI Field Photometry
  22. GRB020127: Chandra Observations and Prospective Counterparts
  23. pre-SN2002ap (SN/GRB?) imaging of M74
  24. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  25. GRB020124, optical observations
  26. GRB 020127, I-band observations starting 3.14-hr after the event
  27. GRB010921 Optical Observations
  28. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  29. GRB020124: Optical observations
  30. GRB 020124: Optical observations
  31. GRB 020124: Optical afterglow
  32. GRB020124(=H1896): Localization of a Long GRB by HETE
  33. Possible optical counterpart to a GRB
  34. GRB011212, Optical Observations
  35. Optical polarization observations for GRB011211
  36. GRB 011211: Detection of the Probable Host Galaxy
  37. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  38. GRB 011130: Optical Observations of X-ray and Radio Sources
  39. GRB 011212: optical observation at Asiago
  40. GRB 011211: Evidence for an Optical Break
  41. GRB 011211: TNG Spectroscopic Observations
  42. optical follow-up of GRB(XRF) 011211
  43. GRB 011212: optical observation at Oslo (relayed)
  44. GRB 011211, Optical Observations
  45. GRB011212, BVRI field photometry
  46. GRB011211, BVRI field photometry
  47. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  48. Fading of the optical source associated of XRF 011211
  49. GRB 011211 Optical Observations: Likely Afterglow
  50. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  51. GRB011130 (XRF011130) Chandra Observations
  52. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  53. GRB 011130, K band observations
  54. GRB011130, optical observations
  55. GRB011130 (=XRF011130): Second Revised Localization by HETE
  56. GRB011130 (XRF011130) SDSS PT i-band observations
  57. XRF011130: Infrared Observations
  58. GRB 011121
  59. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  60. GRB 011121: J-band observations
  61. GRB 011121: NIR observations, host galaxy?
  62. GRB011121: UBRI Observations
  63. GRB 011121 J-Band Astrometry
  64. GRB 011121: Detection of Bright IR Counterpart
  65. GRB011121: possible redshift, continued decay
  66. GRB 011030: TNG K-band observation
  67. XRF011030: J and K band observations
  68. XRF011030: Chandra Observations
  69. GRB011030: Z-band observations
  70. GRB 011030 R band observations
  71. GRB 011030 I-band Observation
  72. The X-ray Flash 011030 ('GRB 011030')
  73. Non-triggered burst 011030 ("GRB 011030")
  74. The Radio Afterglow from the X-ray Rich GRB 011030
  75. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  76. GRB 970828: HST Observations of the Host Galaxy
  77. GRB 000131: HST Detection of the Host Galaxy
  78. GRB 970828: HST Observations of the Host Galaxy
  79. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  80. GRB011019: Subaru Optical Observations
  81. GRB 011030 I-band Observations
  82. GRB 011030 K-band Observations
  83. GRB010921, optical observations
  84. GRB011030 - further refinement WFC position
  85. GRB 011030, Radio observations
  86. GRB011030: radio search
  87. GRB 010921: Possible supernova component
  88. GRB010921, optical observation at early time
  89. GRB 010921, I-band observations
  90. GRB011019, optical observations
  91. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  92. GRB 010921: The afterglow of HETE #1761
  93. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  94. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  95. GRB010923 as seen by BeppoSAX GRBM
  96. GRB010928(=H1770): Localization of a Long GRB by HETE
  97. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  98. GRB010921, negative optical observations
  99. GRB010921 field photometry
  100. H1761: A Bright GRB Detected by HETE

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