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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"

21263 results found.

  1. GRB020405: polarimetric observations
  2. GRB 020531, simultaneous optical observations
  3. GRB020531: Second epoch Chandra observations
  4. GRB020604, optical observations
  5. GRB020604, BVRcIc field photometry
  6. GRB020603, BVRcIc field observations
  7. GRB020531, BVRcIc field photometry
  8. GRB 020531, Radio Observations
  9. IPN triangulation of GRB020604
  10. GRB020531 Optical Observations
  11. GRB020531: Observations with the Chandra X-ray Observatory
  12. GRB020531, optical observations
  13. GRB020531: optical observations
  14. GRB020531(=H2042): Optical Observations
  15. GRB020531(=H2042): Optical Observations
  16. GRB020525, optical observations
  17. IPN triangulation of GRB020525
  18. GRB020405 field photometry at ESO
  19. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  20. XRF 020427
  21. GRB 020124: Optical observations
  22. IPN triangulation of GRB020418
  23. GRB020405: VLT observations of the OT environment
  24. GRB020405: predicted break
  25. GRB 020409: No Evidence for an Optical Afterglow
  26. GRB 020331 Kyoto observation on March 31
  27. GRB 020409
  28. BeppoSAX ALERT: possible GRB020411
  29. X-ray afterglow of GRB020321
  30. GRB020331 optical observations with RIMOTS
  31. GRB020124 optical observations with RIBOTS/RIMOTS
  32. GRB 020321: Candidate X-ray Counterparts
  33. ASM GRB candidate 020406 refined error box
  34. GRB020406(?), optical observations
  35. Short RXTE/ASM transient 020406; may be a GRB
  36. GRB020405, Radio Observations
  37. GRB 020405, U-band observations
  38. IPN localization of GRB020405
  39. GRB020331 NIR observation at KPNO (re-submission)
  40. GRB02033 NIR observation at KPNO
  41. GRB020331 field photometry
  42. GRB 020331, NIR observations
  43. GRB 020322: BeppoSAX observations of the X-ray afterglow
  44. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  45. GRB 020322, Radio observations
  46. Near-Infrared Observations of GRB020322 at TIRGO
  47. GRB 020321, Radio Observations
  48. GRB 020322: Optical Observations
  49. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  50. GRB 020321: Optical observations
  51. GRB020317 BVRI field photometry
  52. GRB011211 revised BVRI field photometry
  53. GRB020305 BVRI field photometry
  54. GRB020322 BVRI field photometry
  55. GRB 020322: Optical Sources and Improved Astrometry
  56. GRB020317: optical observations
  57. GRB020321 optical observations
  58. GRB020321: a faint BeppoSAX detection
  59. GRB 020317 : KISO Optical Observations
  60. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  61. GRB 020305: Optical Observations
  62. GRB020317, optical observations
  63. GRB 020317: Optical observations
  64. GRB020305: Properties of the Candidate Optical Afterglow
  65. GRB 011121: HST Observations reveal an intermediate-time multicolor
  66. GRB011130 (XRF011130) Second Epoch Chandra Observations
  67. XRF/GRB 011030: Detection of the Probable Host Galaxy
  68. GRB020305, optical observations
  69. GRB020305 (=H1939): Localization of a GRB by HETE
  70. HST Imaging of the afterglow and host of GRB 011121
  71. SGR1900+14 activity
  72. IPN Upper Limits to a GRB Associated With SN2002ap
  73. GRB020124 BVRI field photometry
  74. SN2002ap (SN/GRB?) Echelle spectra
  75. SN2002ap (SN/GRB?) optical spectrographic observations
  76. GRB020127 Optical Observations
  77. SN 2002ap (SN/GRB?)
  78. SN2002ap (SN/GRB?) UBVRI Field Photometry
  79. GRB020127: Chandra Observations and Prospective Counterparts
  80. pre-SN2002ap (SN/GRB?) imaging of M74
  81. GRB020124, optical observations
  82. GRB 020127, I-band observations starting 3.14-hr after the event
  83. GRB010921 Optical Observations
  84. GRB020124: Optical observations
  85. GRB 020124: Optical observations
  86. Possible optical counterpart to a GRB
  87. GRB011212, Optical Observations
  88. Optical polarization observations for GRB011211
  89. GRB 011211: Detection of the Probable Host Galaxy
  90. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  91. GRB 011130: Optical Observations of X-ray and Radio Sources
  92. GRB 011130, Radio/X-ray Comparison
  93. GRB 011212: optical observation at Asiago
  94. GRB 011211: Evidence for an Optical Break
  95. GRB 011212: optical observation at Oslo (relayed)
  96. GRB 011211, Optical Observations
  97. GRB011212, BVRI field photometry
  98. GRB011211, BVRI field photometry
  99. Fading of the optical source associated of XRF 011211
  100. GRB011130 (=XRF011130): Further analysis of Chandra Target of

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