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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"

6791 results found.

  1. GRB 071018: Swift-XRT observation
  2. GRB 071017 - Swift XRT observations
  3. GRB 071013: 3rd TLS Epoch - constraints on variability
  4. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  5. GRB 071011: Swift-XRT refined analysis
  6. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  7. GRB 071011, Optical afterglow
  8. GRB 071010: Swift-XRT observation
  9. GRB071008: Swift-XRT observation
  10. GRB 071010: Keck Observations of the Afterglow
  11. GRB 071003: XRT refined analysis
  12. GRB070920A: MAGIC telescope GeV observation
  13. GRB 070810B: further XRT analysis
  14. GRB 071003: Possible rebrightening
  15. GRB 071003: Swift XRT position
  16. GRB 071003 Optical observations
  17. GRB 071001: Swift-XRT Team refined analysis
  18. GRB070925: Swift-XRT Position
  19. GRB 070920B: XRT observations
  20. GRB 070923: Galaxies within BAT localization
  21. INTEGRAL ToO observations of SGR1806-20
  22. GRB 070917: Confirmation of the X-ray afterglow
  23. GRB 070920, Swift-BAT refined analysis
  24. GRB 070917: Swift-XRT observations
  25. GRB 070917: R band observations
  26. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  27. GRB 070911: PAIRITEL IR Observations
  28. GRB 070911: Swift XRT refined analysis
  29. GRB 070731: Swift/UVOT Upper Limit
  30. IPN Localization of GRB 070821 (long, very bright)
  31. GRB 070810B: XRT refined analysis
  32. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  33. GRB 070810: Swift-XRT Team Refined Analysis
  34. GRB 070809: Swift-XRT refined analysis
  35. GRB 070805: Swift XRT initial analysis.
  36. GRB 070724B: Swift-XRT afterglow confirmation
  37. GRB 070802: Swift-XRT refined analysis
  38. GRB 070802: GROND J band candidate
  39. GRB 070729: Swift-XRT refined analysis
  40. GRB 070729: Magellan NIR Observations
  41. GRB 070724: P60 and Gemini Observations
  42. GRB 070724: Swift-XRT Team refined analysis
  43. GRB 070721A: Swift/XRT refined analysis
  44. GRB 070616: No Evidence for I Band Afterglow
  45. GRB 070714A: Swift XRT refined analysis
  46. GRB070714B: Swift-XRT refined analysis
  47. GRB 070707: Swift-XRT follow-up observations
  48. Swift XRT observation of GRB 070707
  49. GRB 070628: Swift XRT refined analysis
  50. GRB070621: Swift XRT refined analysis
  51. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  52. GRB 070616: Swift XRT refined circular
  53. SWIFT J195509.6+261406 (GRB 070610): further observations
  54. GRB 070612B: Swift-XRT refined analysis
  55. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  56. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  57. GRB 070610: Swift-XRT refined analysis
  58. GRB 070611: Swift-XRT refined analysis
  59. GRB 070611; Swift-XRT position
  60. GRB 070610; Swift-XRT position
  61. GRB 070529: Swift-XRT refined analysis
  62. GRB 070521: Swift-XRT refined analysis
  63. GRB 070521: Keck imaging
  64. GRB070521: Gemini Observations
  65. GROND upper limits of GRB 070521
  66. GRB 070520B: Swift-XRT refined analysis
  67. GRB 070520A: Swift-XRT refined analysis
  68. GRB 070518: Swift-XRT refined analysis
  69. RHESSI Spectrum of GRB070508
  70. GRB 070508: Swift-XRT refined analysis
  71. GRB070412: MAGIC telescope GeV observation
  72. GRB 070429A: Swift XRT further analysis
  73. GRB 070420: Swift XRT refined analysis
  74. GBR 070419A: Swift/XRT refined analysis
  75. GRB 070419B: Swift XRT refined analysis
  76. GRB 070419A: Optical and IR observations with KANATA
  77. GRB 070418: Optical and IR observations with KANATA
  78. GRB 070406: Swift XRT refined analysis
  79. GRB 070411: Swift-XRT refined analysis
  80. GRB 070406: Swift XRT team further analysis
  81. Suzaku ToO observation of SGR 1806-20
  82. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  83. GRB 070406: Gemini South Imaging and XRT analysis
  84. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  85. GRB 070406: SARA upper limit
  86. GRB 070330: Swift-XRT refined analysis
  87. Konus-Wind observation of GRB 070328
  88. GRB 070328: Swift/XRT Refined Analysis
  89. GRB070208: optical observations
  90. GRB 070318: Gemini + Magellan spectra
  91. GRB070318: Swift-XRT refined analysis
  92. GRB 070311: Swift-XRT refined analysis
  93. GRB 070125: Chandra X-ray Confirmation of Jet Break
  94. GRB 070125: X-ray light curve analysis
  95. GRB 070306: XRT Team Refined Analysis
  96. GRB 070306: Optical and IR observations with KANATA
  97. GRB070224: Swift-XRT Refined Analysis
  98. GRB 070223: Optical-IR observation with KANATA
  99. GRB 070223: Swift-XRT Refined Analysis
  100. Konus-Wind and Konus-A observations of GRB 070220

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