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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"

28068 results found.

  1. GRB 020604, optical observations
  2. GRB 020531/Candidate Redshift
  3. GRB020531: Detection of Candidate Host Galaxy
  4. GRB 020418, optical/near-IR observations
  5. GRB020531: Upper Limit for Detection of Two TAROT Sources
  6. GRB 020603: Optical observations
  7. IPN detection of possible bursts from SGR1806-20
  8. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  9. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  10. HST detection of the likely host galaxy of GRB 020124
  11. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  12. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  13. GRB020321 : Optical observations.
  14. GRB020331: Third Epoch and Revised Second Epoch Optical
  15. The end of BSAX GRB activities
  16. GRB 020418: Optical observations
  17. GRB 020124: Optical observations
  18. GRB 020418: Optical observations
  19. GRB020410: BeppoSAX NFI observations refined analysis
  20. Mars Odyssey joins the IPN
  21. GRB020405: predicted break
  22. GRB 020409: Optical observations
  23. GRB 020409, No Optical Detection to R = 22
  24. GRB 020409: No Evidence for an Optical Afterglow
  25. GRB 020409, 2nd epoch optical observations
  26. GRB 020331 Kyoto observation on March 31
  27. GRB 020409
  28. GRB 020409, No Optical Detection to R = 20
  29. GRB020406(?), optical observations
  30. X-ray afterglow of GRB020321
  31. GRB020331: Confirmation of Afterglow Candidate with Magellan
  32. ASM GRB candidate 020406 refined error box
  33. GRB 020405: Moderate-resolution spectroscopy
  34. GRB020331: Optical Observations of Afterglow Candidate
  35. GRB020406(?), optical observations
  36. Revised Photometry of the Optical Afterglow of GRB 020405
  37. GRB 020331: Candidate Optical Afterglow
  38. GRB 020405: Decay index
  39. GRB020405, Radio Observations
  40. GRB020405: VLT spectroscopy
  41. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  42. GRB 020405, U-band observations
  43. GRB 020405: Optical afterglow candidate
  44. GRB011212: Optical Observations
  45. GRB 020331: NIR Observations
  46. GRB 020331: NIR Observations
  47. GRB020331 NIR observation at KPNO (re-submission)
  48. GRB02033 NIR observation at KPNO
  49. GRB020331 field photometry
  50. GRB 020331, NIR observations
  51. GRB 020331: Optical observations
  52. GRB 020322: BeppoSAX observations of the X-ray afterglow
  53. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  54. GRB 020322, Radio observations
  55. Near-Infrared Observations of GRB020322 at TIRGO
  56. GRB 020321, Radio Observations
  57. GRB 020322: Optical Observations
  58. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  59. GRB 020321: Optical observations
  60. GRB020317 BVRI field photometry
  61. GRB 020322 optical observations
  62. GRB020322: Candidate Optical Afterglow
  63. GRB 020322 optical observation
  64. GRB020322, optical observations
  65. GRB 020322: Optical candidate
  66. GRB 020321: Optical observations
  67. GRB 011121: Fourth Epoch of HST Imaging
  68. GRB020321: BeppoSAX/NFI Observations
  69. GRB020321: a faint BeppoSAX detection
  70. GRB020305: NIR observations
  71. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  72. GRB 020305: Optical Observations
  73. GRB020317, optical observations
  74. GRB 020317: Optical observations
  75. GRB 011121: Third HST Epoch
  76. GRB020305: Properties of the Candidate Optical Afterglow
  77. GRB 011121: HST Observations reveal an intermediate-time multicolor
  78. GRB011121, possible supernova association
  79. GRB020305: Subaru Optical Observations
  80. GRB 020305: Optical observations
  81. XRF/GRB 011030: Detection of the Probable Host Galaxy
  82. GRB 020305: Candidate optical afterglow
  83. GRB020305 (=H1939): Localization of a GRB by HETE
  84. HST Imaging of the afterglow and host of GRB 011121
  85. GRB 010921: HST Observations
  86. IPN detection and localization of Cygnus X-1 flares
  87. GRB020127: Further VLA Observations of Possible Counterparts
  88. IPN detection of further SGR1900+14 activity
  89. IPN/HETE Detection of Bursts from SGR1900+14
  90. GRB020127: Palomar and VLA Observations of Possible Counterparts
  91. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  92. Type Ib/c SN2002ap (SN/GRB?)
  93. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  94. IPN detection of further activity from SGR1806-20
  95. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  96. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  97. GRB 020124 Optical Observations
  98. GRB 020124: Optical afterglow
  99. GRB020124(=H1896): Localization of a Long GRB by HETE
  100. GRB 011211: Detection of the Probable Host Galaxy

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