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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"

37515 results found.

  1. GRB020322, optical observations
  2. GRB 020322: Optical candidate
  3. GRB020322: BeppoSAX/NFI Observations
  4. Bepposax GRB020322 The second springtime BSAX GRB
  5. GRB 020321: Optical observations
  6. GRB 011121: Fourth Epoch of HST Imaging
  7. GRB020317: optical observations
  8. GRB020321 optical observations
  9. GRB020321: BeppoSAX/NFI Observations
  10. GRB020321: a faint BeppoSAX detection
  11. GRB 020317 : KISO Optical Observations
  12. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  13. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  14. GRB 020305: Optical Observations
  15. GRB020317, optical observations
  16. GRB 020317: Optical observations
  17. GRB 011121: Third HST Epoch
  18. GRB020305: Properties of the Candidate Optical Afterglow
  19. GRB 011121: HST Observations reveal an intermediate-time multicolor
  20. GRB011121, possible supernova association
  21. GRB011130 (XRF011130) Second Epoch Chandra Observations
  22. GRB020305: Subaru Optical Observations
  23. GRB 020305: Optical observations
  24. XRF/GRB 011030 Images
  25. XRF/GRB 011030: Detection of the Probable Host Galaxy
  26. GRB 020305: Candidate optical afterglow
  27. Type Ic SN2002bl (SN/GRB?) Radio Observations
  28. GRB020305: Optical Observations
  29. IPN triangulation of GRB020305 (HETE 1939)
  30. GRB020305 (=H1939): Localization of a GRB by HETE
  31. GRB 020305: Optical observations
  32. HST Imaging of the afterglow and host of GRB 011121
  33. GRB 010921: HST Observations
  34. IPN detection and localization of Cygnus X-1 flares
  35. GRB020127: Further VLA Observations of Possible Counterparts
  36. IPN detection of further SGR1900+14 activity
  37. SGR1900+14 activity
  38. IPN/HETE Detection of Bursts from SGR1900+14
  39. IPN Upper Limits to a GRB Associated With SN2002ap
  40. GRB020124 BVRI field photometry
  41. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  42. SN2002ap (SN/GRB?) Echelle spectra
  43. SN2002ap (SN/GRB?) optical spectrographic observations
  44. GRB020127 Optical Observations
  45. SN 2002ap (SN/GRB?)
  46. SN2002ap (SN/GRB?) UBVRI Field Photometry
  47. GRB020127: Chandra Observations and Prospective Counterparts
  48. pre-SN2002ap (SN/GRB?) imaging of M74
  49. SN 2002ap (hypernova / GRB ??): special list on VSNET
  50. Type Ib/c SN2002ap (SN/GRB?)
  51. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  52. GRB020124, optical observations
  53. GRB020127: Optical observations
  54. GRB 020127, I-band observations starting 3.14-hr after the event
  55. IPN detection of further activity from SGR1806-20
  56. IPN triangulation of GRB020127 (=H1902)
  57. GRB010921 Optical Observations
  58. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  59. GRB020124: Optical observations
  60. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  61. GRB020124: Optical observations
  62. GRB 020124: Optical observations
  63. GRB 020124 Optical Observations
  64. IPN triangulation of GRB020124 (HETE 1896)
  65. IPN observations of SGR1806-20
  66. GRB 020124: Optical afterglow
  67. GRB020124(=H1896): Localization of a Long GRB by HETE
  68. GRB optical counterpart candidate in GCN 1217 is M dwarf
  69. Possible optical counterpart to a GRB
  70. GRB011212, Optical Observations
  71. GRB 011211: Detection of the Probable Host Galaxy
  72. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  73. GRB 011211, spectrum and optical photometry
  74. GRB 011130: Optical Observations of X-ray and Radio Sources
  75. GRB 011130, Radio/X-ray Comparison
  76. GRB 011212: optical observation at Asiago
  77. GRB 011211: Evidence for an Optical Break
  78. GRB 011211: TNG Spectroscopic Observations
  79. optical follow-up of GRB(XRF) 011211
  80. GRB 011212: optical observation at Oslo (relayed)
  81. GRB 011211: Optical Spectroscopy
  82. GRB 011211, Optical Observations
  83. GRB011212, BVRI field photometry
  84. GRB011211, BVRI field photometry
  85. GRB011212: Optical observations
  86. GRB 011211: BVRi-band photometry
  87. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  88. Fading of the optical source associated of XRF 011211
  89. GRB 011211 Optical Observations: Likely Afterglow
  90. BeppoSAX Alert: GRB011211(=XRF011211)
  91. GRB 011130: Optical Observations of Chandra Sources
  92. GRB 011130: Optical Observations of Chandra sources
  93. GRB 011130: Magellan spectroscopy
  94. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  95. GRB011130, optical observations
  96. GRB 011130, K band observations
  97. GRB011130, optical observations
  98. GRB 011130 I-band Observation
  99. GRB011130 (XRF011130) optical observations
  100. GRB011130 (XRF011130) SDSS PT i-band observations

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