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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"

27401 results found.

  1. Short RXTE/ASM transient 020406; may be a GRB
  2. GRB020405, Radio Observations
  3. GRB 020405, U-band observations
  4. GRB011212: Optical Observations
  5. GRB 020331: NIR Observations
  6. GRB020331 NIR observation at KPNO (re-submission)
  7. GRB02033 NIR observation at KPNO
  8. GRB020331 field photometry
  9. GRB 020331, NIR observations
  10. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  11. GRB 020322: BeppoSAX observations of the X-ray afterglow
  12. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  13. Near-Infrared Observations of GRB020322 at TIRGO
  14. GRB 020321, Radio Observations
  15. GRB 020322: Optical Observations
  16. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  17. GRB 020321: Optical observations
  18. GRB020317 BVRI field photometry
  19. GRB011211 revised BVRI field photometry
  20. GRB020305 BVRI field photometry
  21. GRB020322 BVRI field photometry
  22. GRB 020322: Optical Sources and Improved Astrometry
  23. GRB020317: optical observations
  24. GRB020321 optical observations
  25. GRB020321: a faint BeppoSAX detection
  26. GRB 020317 : KISO Optical Observations
  27. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  28. GRB 020305: Optical Observations
  29. GRB020317, optical observations
  30. GRB 020317: Optical observations
  31. GRB 011121: Third HST Epoch
  32. GRB020305: Properties of the Candidate Optical Afterglow
  33. GRB 011121: HST Observations reveal an intermediate-time multicolor
  34. GRB011130 (XRF011130) Second Epoch Chandra Observations
  35. GRB020305: Subaru Optical Observations
  36. XRF/GRB 011030: Detection of the Probable Host Galaxy
  37. GRB 020305: Candidate optical afterglow
  38. GRB020305, optical observations
  39. IPN triangulation of GRB020305 (HETE 1939)
  40. GRB020305 (=H1939): Localization of a GRB by HETE
  41. HST Imaging of the afterglow and host of GRB 011121
  42. IPN detection and localization of Cygnus X-1 flares
  43. SGR1900+14 activity
  44. IPN Upper Limits to a GRB Associated With SN2002ap
  45. GRB020124 BVRI field photometry
  46. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  47. SN2002ap (SN/GRB?) Echelle spectra
  48. GRB020127 Optical Observations
  49. SN 2002ap in M74
  50. SN2002ap (SN/GRB?) UBVRI Field Photometry
  51. GRB020127: Chandra Observations and Prospective Counterparts
  52. pre-SN2002ap (SN/GRB?) imaging of M74
  53. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  54. GRB020124, optical observations
  55. GRB 020127, I-band observations starting 3.14-hr after the event
  56. GRB010921 Optical Observations
  57. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  58. GRB020124: Optical observations
  59. GRB 020124: Optical observations
  60. GRB 020124: Optical afterglow
  61. GRB020124(=H1896): Localization of a Long GRB by HETE
  62. Possible optical counterpart to a GRB
  63. GRB011212, Optical Observations
  64. Optical polarization observations for GRB011211
  65. GRB 011211: Detection of the Probable Host Galaxy
  66. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  67. GRB 011130: Optical Observations of X-ray and Radio Sources
  68. GRB 011212: optical observation at Asiago
  69. GRB 011211: Evidence for an Optical Break
  70. GRB 011211: TNG Spectroscopic Observations
  71. optical follow-up of GRB(XRF) 011211
  72. GRB 011212: optical observation at Oslo (relayed)
  73. GRB 011211, Optical Observations
  74. GRB011212, BVRI field photometry
  75. GRB011211, BVRI field photometry
  76. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  77. Fading of the optical source associated of XRF 011211
  78. GRB 011211 Optical Observations: Likely Afterglow
  79. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  80. GRB011130 (XRF011130) Chandra Observations
  81. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  82. GRB 011130, K band observations
  83. GRB011130, optical observations
  84. GRB011130 (=XRF011130): Second Revised Localization by HETE
  85. GRB011130 (XRF011130) SDSS PT i-band observations
  86. XRF011130: Infrared Observations
  87. GRB 011121
  88. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  89. GRB 011121: J-band observations
  90. GRB 011121: NIR observations, host galaxy?
  91. GRB011121: UBRI Observations
  92. GRB 011121 J-Band Astrometry
  93. GRB 011121: Detection of Bright IR Counterpart
  94. GRB011121: possible redshift, continued decay
  95. GRB 011030: TNG K-band observation
  96. XRF011030: J and K band observations
  97. XRF011030: Chandra Observations
  98. GRB011030: Z-band observations
  99. GRB 011030 R band observations
  100. GRB 011030 I-band Observation

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