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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"

27321 results found.

  1. HST detection of the likely host galaxy of GRB 020124
  2. GRB020405 field photometry at ESO
  3. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  4. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  5. GRB020321 : Optical observations.
  6. XRF 020427
  7. GRB 020124: Optical observations
  8. IPN triangulation of GRB020418
  9. GRB020405: VLT observations of the OT environment
  10. IPN triangulation of GRB020413
  11. GRB020405: predicted break
  12. GRB 020409: No Evidence for an Optical Afterglow
  13. GRB 020331 Kyoto observation on March 31
  14. GRB020410: BeppoSAX NFI observation
  15. X-ray afterglow of GRB020321
  16. GRB020331 optical observations with RIMOTS
  17. GRB020124 optical observations with RIBOTS/RIMOTS
  18. GRB 020321: Candidate X-ray Counterparts
  19. GRB020406(?), optical observations
  20. GRB 020405: Decay index
  21. Short RXTE/ASM transient 020406; may be a GRB
  22. GRB020405, Radio Observations
  23. GRB 020405, U-band observations
  24. GRB011212: Optical Observations
  25. GRB 020331: NIR Observations
  26. GRB020331 NIR observation at KPNO (re-submission)
  27. GRB02033 NIR observation at KPNO
  28. GRB020331 field photometry
  29. GRB 020331, NIR observations
  30. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  31. GRB 020322: BeppoSAX observations of the X-ray afterglow
  32. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  33. Near-Infrared Observations of GRB020322 at TIRGO
  34. GRB 020321, Radio Observations
  35. GRB 020322: Optical Observations
  36. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  37. GRB 020321: Optical observations
  38. GRB020317 BVRI field photometry
  39. GRB011211 revised BVRI field photometry
  40. GRB020305 BVRI field photometry
  41. GRB020322 BVRI field photometry
  42. GRB 020322: Optical Sources and Improved Astrometry
  43. GRB020317: optical observations
  44. GRB020321 optical observations
  45. GRB020321: a faint BeppoSAX detection
  46. GRB 020317 : KISO Optical Observations
  47. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  48. GRB 020305: Optical Observations
  49. GRB020317, optical observations
  50. GRB 020317: Optical observations
  51. GRB 011121: Third HST Epoch
  52. GRB020305: Properties of the Candidate Optical Afterglow
  53. GRB 011121: HST Observations reveal an intermediate-time multicolor
  54. GRB011130 (XRF011130) Second Epoch Chandra Observations
  55. GRB020305: Subaru Optical Observations
  56. XRF/GRB 011030: Detection of the Probable Host Galaxy
  57. GRB 020305: Candidate optical afterglow
  58. GRB020305, optical observations
  59. IPN triangulation of GRB020305 (HETE 1939)
  60. GRB020305 (=H1939): Localization of a GRB by HETE
  61. HST Imaging of the afterglow and host of GRB 011121
  62. IPN detection and localization of Cygnus X-1 flares
  63. SGR1900+14 activity
  64. IPN Upper Limits to a GRB Associated With SN2002ap
  65. GRB020124 BVRI field photometry
  66. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  67. SN2002ap (SN/GRB?) Echelle spectra
  68. GRB020127 Optical Observations
  69. SN 2002ap in M74
  70. SN2002ap (SN/GRB?) UBVRI Field Photometry
  71. GRB020127: Chandra Observations and Prospective Counterparts
  72. pre-SN2002ap (SN/GRB?) imaging of M74
  73. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  74. GRB020124, optical observations
  75. GRB 020127, I-band observations starting 3.14-hr after the event
  76. GRB010921 Optical Observations
  77. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  78. GRB020124: Optical observations
  79. GRB 020124: Optical observations
  80. GRB 020124: Optical afterglow
  81. GRB020124(=H1896): Localization of a Long GRB by HETE
  82. Possible optical counterpart to a GRB
  83. GRB011212, Optical Observations
  84. Optical polarization observations for GRB011211
  85. GRB 011211: Detection of the Probable Host Galaxy
  86. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  87. GRB 011130: Optical Observations of X-ray and Radio Sources
  88. GRB 011212: optical observation at Asiago
  89. GRB 011211: Evidence for an Optical Break
  90. GRB 011211: TNG Spectroscopic Observations
  91. optical follow-up of GRB(XRF) 011211
  92. GRB 011212: optical observation at Oslo (relayed)
  93. GRB 011211, Optical Observations
  94. GRB011212, BVRI field photometry
  95. GRB011211, BVRI field photometry
  96. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  97. Fading of the optical source associated of XRF 011211
  98. GRB 011211 Optical Observations: Likely Afterglow
  99. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  100. GRB011130 (XRF011130) Chandra Observations

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