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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"
  1. GRB 080130: further Swift XRT observations confirm fading source
  2. GRB 080129: Swift/UVOT Refined Upper Limits
  3. Swift/UVOT observations of GRB080130
  4. GRB 080130: REM NIR observations
  5. GRB 080130(?): Swift XRT observation
  6. GRB 080130?: Detection of a possible burst by BATSS
  7. GRB 080129: Optical observations from OSN
  8. GRB 080129: Swift-XRT refined analysis
  9. X-ray transient in NGC 2770: RTT150 optical observations
  10. GRB 080129: KAIT optical limits
  11. GRB 080123: Early afterglow detection with BATSS (BAT Slew Survey)
  12. GRB 080129: optical limit by Pi of the Sky
  13. GRB 080129, Swift-BAT refined analysis
  14. GRB 080129: TAROT La Silla observatory optical observations
  15. GRB 080129: Gemini-South photometry
  16. GRB 080129: GROND detection in all bands, and fading
  17. GRB 080129: GROND detection of the optical/NIR afterglow, and fading
  18. GRB 080129: Enhanced Swift-XRT position
  19. GRB 080129: Gemini-South Imaging Observations
  20. GRB 080129: Swift XRT position
  21. GRB 080129 (?): UVOT Upper Limits
  22. GRB 080129 (?): Swift detection of a possible burst
  23. A new website of high-level data products for Swift GRBs
  24. GRB 080121: Upper limit on X-ray afterglow
  25. GRB 080123 : Suzaku WAM observation of the prompt emission
  26. Swift trigger(=301779) is not a GRB
  27. Transient 080109/SN 2008D: Spectroscopic Evolution
  28. GRB 080122: pseudo-z= 1.93 from prompt emission spectrum
  29. Konus-Wind observation of GRB 080122
  30. GRB 080122 : Suzaku WAM observation of the prompt emission
  31. GRB 080121: Swift/UVOT upper limits
  32. SNe 2008D and 2007uy: Chandra Detections
  33. GRB 080121 position was incorrect
  34. GRB 080121: Enhanced Swift-XRT position
  35. Two non-burst Swift SubThreshold triggers
  36. Transient 080109/SN 2008D: Spectroscopic Evolution and Re-Classification
  37. IPN triangulation of GRB080122
  38. GRB 080121: Nearby SDSS galaxies
  39. GRB 080121: Swift-BAT detection of a very weak, short burst
  40. GRB 080123: Swift-XRT refined analysis
  41. GRB 080123: Swift/UVOT refined analysis
  42. X-ray transient in NGC 2770: RTT150 optical observations
  43. GRB 080123, Swift-BAT refined analysis
  44. GRB 080123: Enhanced Swift-XRT position
  45. GRB 080123: Swift detection of a short burst
  46. GRB 080120: GROND confirmation of the optical afterglow
  47. XRF 080109 / SN 2008D: GMRT radio observation at 1280 MHz
  48. VLA radio upper limit on GRB 080120
  49. GRB 080120: Swift-XRT refined analysis
  50. UVOT detection of GRB080120
  51. GRB 080120: GROND detection
  52. GRB 080120 : Planned XMM-Newton observation
  53. GRB080120: Swift XRT position
  54. GRB 080120: a long GRB detected by INTEGRAL
  55. XRF 080109 / SN 2008D: 1.4 GHz WSRT Radio Observations
  56. Transient in NGC2770 / SN2008D: Metallicity of nearby HII regions
  57. Transient XRF 080109 / SN 2008D: Mount Abu NIR observations
  58. XRF 080109 / SN 2008D: WSRT Radio Detection
  59. Transient 080109/ SN 2008D, metallicity of the host galaxy
  60. Transient 080109/ SN 2008D, IR Spectrum
  61. XRF 080109 / SN 2008D: optical observations
  62. NGC 2770B has the same redshift as NGC 2770
  63. Swift UVOT Monitoring of the SN 2008D Brightening (Transient in NGC 2770)
  64. XRF 080109 / SN 2008D: spectroscopic evolution
  65. XRF 080109 / SN 2008D: UKIRT JHK imaging
  66. optical observations, XRT in NGC 2770
  67. XRF 080109/SN 2008D: PROMPT Optical Imaging
  68. Gemini-South observations of XRF 080109 / SN 2008D
  69. Swift observations of the X-ray transient in NGC 2770 (aka SN2008D)
  70. Discovery of Radio Emission from Transient in NGC 2770
  71. XRF 080109 in NGC2770: NIR observations at TNG
  72. XRB 080109/SN 2008D: Early decline in brightness and change in colors
  73. XRB 080109/SN 2008D:PAIRITEL NIR observations and t_0 from Swift
  74. XRF 080109 in NGC2770: Detectable Superluminal Motion
  75. Detailed Spectroscopic ID of SN 2008D (Transient in NGC 2770)
  76. XRF in NGC 2770: Search for X-ray periodicity
  77. Spectroscopic classification of SN 2008D (Transient in NGC 2770)
  78. Refined Swift-XRT analysis of the transient in NGC 2770
  79. Transient in NGC 2770: spectroscopic evidence for a SN
  80. Refined Swift UVOT Analysis of SN 2008D (Transient in NGC 2770)
  81. Opticall follow-ups for the X-ray transient in NGC 2770
  82. X-ray transient in NGC 2770: Optical observations with Astrotel-Caucasus
  83. Optical Spectroscopy of the Transient in NGC 2770
  84. Swift UVOT Observations of the X-ray transient in NGC 2770
  85. Early OT detection of XRF in NGC 2770 in Asiago frames
  86. Bright X-ray transient / possible XRF in NGC 2770: TNG R imaging
  87. Possible XRF in NGC 2770 - NOT observations of the optical counterpart
  88. Bright X-ray Transient (a XRF? ) in NGC 2770 - A SN optical counterpart?
  89. Bright X-ray Transient in NGC 2770 - A low-luminosity XRF?
  90. GRB 071227: Suzaku WAM observation of the prompt emission
  91. GRB 071227: optical afterglow
  92. Further Swift-BAT analysis of GRB 071227
  93. Konus-Wind observation of GRB 071227
  94. GRB 071227: Magellan redshift confirmation
  95. GRB 071227: Swift-XRT refined analysis
  96. GRB 071227: VLT probable redshift of the candidate host galaxy
  97. GRB 071227: Magellan observations
  98. GRB071227: Swift/UVOT refined analysis
  99. GRB 071227: REM NIR and Optical observations
  100. Swift-BAT refined analysis of short GRB 071227

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