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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"

27549 results found.

  1. Mars Odyssey joins the IPN
  2. GRB020405: predicted break
  3. GRB 020409: Optical observations
  4. GRB 020409, No Optical Detection to R = 22
  5. GRB 020409: No Evidence for an Optical Afterglow
  6. GRB 020409, 2nd epoch optical observations
  7. GRB 020331 Kyoto observation on March 31
  8. GRB 020409
  9. GRB 020409, No Optical Detection to R = 20
  10. GRB020406(?), optical observations
  11. X-ray afterglow of GRB020321
  12. GRB020331: Confirmation of Afterglow Candidate with Magellan
  13. ASM GRB candidate 020406 refined error box
  14. GRB 020405: Moderate-resolution spectroscopy
  15. GRB020331: Optical Observations of Afterglow Candidate
  16. GRB020406(?), optical observations
  17. Revised Photometry of the Optical Afterglow of GRB 020405
  18. GRB 020331: Candidate Optical Afterglow
  19. GRB 020405: Decay index
  20. GRB020405, Radio Observations
  21. GRB020405: VLT spectroscopy
  22. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  23. GRB 020405, U-band observations
  24. GRB 020405: Optical afterglow candidate
  25. GRB011212: Optical Observations
  26. GRB 020331: NIR Observations
  27. GRB 020331: NIR Observations
  28. GRB020331 NIR observation at KPNO (re-submission)
  29. GRB02033 NIR observation at KPNO
  30. GRB020331 field photometry
  31. GRB 020331, NIR observations
  32. GRB 020331: Optical observations
  33. GRB 020322: BeppoSAX observations of the X-ray afterglow
  34. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  35. GRB 020322, Radio observations
  36. Near-Infrared Observations of GRB020322 at TIRGO
  37. GRB 020321, Radio Observations
  38. GRB 020322: Optical Observations
  39. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  40. GRB 020321: Optical observations
  41. GRB020317 BVRI field photometry
  42. GRB 020322 optical observations
  43. GRB020322: Candidate Optical Afterglow
  44. GRB 020322 optical observation
  45. GRB020322, optical observations
  46. GRB 020322: Optical candidate
  47. GRB 020321: Optical observations
  48. GRB 011121: Fourth Epoch of HST Imaging
  49. GRB020321: BeppoSAX/NFI Observations
  50. GRB020321: a faint BeppoSAX detection
  51. GRB020305: NIR observations
  52. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  53. GRB 020305: Optical Observations
  54. GRB020317, optical observations
  55. GRB 020317: Optical observations
  56. GRB 011121: Third HST Epoch
  57. GRB020305: Properties of the Candidate Optical Afterglow
  58. GRB 011121: HST Observations reveal an intermediate-time multicolor
  59. GRB011121, possible supernova association
  60. GRB020305: Subaru Optical Observations
  61. GRB 020305: Optical observations
  62. XRF/GRB 011030: Detection of the Probable Host Galaxy
  63. GRB 020305: Candidate optical afterglow
  64. GRB020305 (=H1939): Localization of a GRB by HETE
  65. HST Imaging of the afterglow and host of GRB 011121
  66. GRB 010921: HST Observations
  67. IPN detection and localization of Cygnus X-1 flares
  68. GRB020127: Further VLA Observations of Possible Counterparts
  69. IPN detection of further SGR1900+14 activity
  70. IPN/HETE Detection of Bursts from SGR1900+14
  71. GRB020127: Palomar and VLA Observations of Possible Counterparts
  72. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  73. Type Ib/c SN2002ap (SN/GRB?)
  74. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  75. IPN detection of further activity from SGR1806-20
  76. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  77. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  78. GRB 020124 Optical Observations
  79. GRB 020124: Optical afterglow
  80. GRB020124(=H1896): Localization of a Long GRB by HETE
  81. GRB 011211: Detection of the Probable Host Galaxy
  82. Color indices of the afterglow of GRB011211
  83. GRB011212: Optical observations at Gunma
  84. GRB 011211, spectrum and optical photometry
  85. GRB 011211: Evidence for an Optical Break
  86. GRB 011211: TNG Spectroscopic Observations
  87. optical follow-up of GRB(XRF) 011211
  88. GRB 011212: optical observation at Oslo (relayed)
  89. GRB 011211, Optical Observations
  90. GRB011212: Optical observations
  91. GRB 011211: BVRi-band photometry
  92. GRB 011211 Optical Observations: Likely Afterglow
  93. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  94. GRB 011130: Magellan spectroscopy
  95. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  96. GRB011130, optical observations
  97. GRB 011130, K band observations
  98. GRB011130, optical observations
  99. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  100. GRB011130 (=XRF011130): Revised Localization of an X-ray

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