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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"

45294 results found.

  1. Transient 080109/ SN 2008D, metallicity of the host galaxy
  2. Transient 080109/ SN 2008D, IR Spectrum
  3. XRF 080109 / SN 2008D: optical observations
  4. NGC 2770B has the same redshift as NGC 2770
  5. Swift UVOT Monitoring of the SN 2008D Brightening (Transient in NGC 2770)
  6. XRF 080109 / SN 2008D: spectroscopic evolution
  7. XRF 080109 / SN 2008D: UKIRT JHK imaging
  8. optical observations, XRT in NGC 2770
  9. XRF 080109/SN 2008D: PROMPT Optical Imaging
  10. Gemini-South observations of XRF 080109 / SN 2008D
  11. Swift observations of the X-ray transient in NGC 2770 (aka SN2008D)
  12. Discovery of Radio Emission from Transient in NGC 2770
  13. XRF 080109 in NGC2770: NIR observations at TNG
  14. XRB 080109/SN 2008D: Early decline in brightness and change in colors
  15. XRB 080109/SN 2008D:PAIRITEL NIR observations and t_0 from Swift
  16. XRF 080109 in NGC2770: Detectable Superluminal Motion
  17. Detailed Spectroscopic ID of SN 2008D (Transient in NGC 2770)
  18. XRF in NGC 2770: Search for X-ray periodicity
  19. Spectroscopic classification of SN 2008D (Transient in NGC 2770)
  20. Refined Swift-XRT analysis of the transient in NGC 2770
  21. Transient in NGC 2770: spectroscopic evidence for a SN
  22. Refined Swift UVOT Analysis of SN 2008D (Transient in NGC 2770)
  23. Opticall follow-ups for the X-ray transient in NGC 2770
  24. X-ray transient in NGC 2770: Optical observations with Astrotel-Caucasus
  25. Optical Spectroscopy of the Transient in NGC 2770
  26. Swift UVOT Observations of the X-ray transient in NGC 2770
  27. Early OT detection of XRF in NGC 2770 in Asiago frames
  28. Bright X-ray transient / possible XRF in NGC 2770: TNG R imaging
  29. Possible XRF in NGC 2770 - NOT observations of the optical counterpart
  30. Bright X-ray Transient (a XRF? ) in NGC 2770 - A SN optical counterpart?
  31. Bright X-ray Transient in NGC 2770 - A low-luminosity XRF?
  32. GRB 071227: Suzaku WAM observation of the prompt emission
  33. GRB 071227: optical afterglow
  34. Further Swift-BAT analysis of GRB 071227
  35. Konus-Wind observation of GRB 071227
  36. GRB 071227: Magellan redshift confirmation
  37. GRB 071227: Swift-XRT refined analysis
  38. GRB 071227: VLT probable redshift of the candidate host galaxy
  39. GRB 071227: Magellan observations
  40. GRB071227: Swift/UVOT refined analysis
  41. GRB 071227: REM NIR and Optical observations
  42. Swift-BAT refined analysis of short GRB 071227
  43. GRB 071227: Swift detection of a burst
  44. GRB071020: optical observations
  45. GRB 070429B: Possible UVOT Detection of an Optical Afterglow
  46. Swift-BAT trigger 298308 is not a GRB
  47. GRB 071208?: Swift detection of a possible burst
  48. IBAS Alert #4772 in not a GRB
  49. GRB 071125: Suzaku WAM observation of the prompt emission
  50. GRB 070429B: Probable host galaxy and redshift
  51. GRB 071129, Swift-BAT refined analysis
  52. GRB 071129: Swift detection of a burst
  53. Konus-Wind and Konus-A observations of GRB 071125
  54. IPN triangulation of very bright GRB 071125
  55. GRB 071112C: Optical/NIR observations
  56. Disregard the "GRB 071126" position
  57. GRB 071126: Enhanced Swift-XRT position
  58. VLA radio detection of GRB 071122
  59. GRB071122: Swift/UVOT Observations
  60. GRB071104: NIR Afterglow Candidate at TNG
  61. GRB 071122: MASTER optical observation
  62. GRB 071122, Swift-BAT refined analysis
  63. GRB 071122 Swift XRT position update sent in error.
  64. GRB 071122 Swift-XRT refined analysis
  65. GRB 071122: Corrected P60 Coordinates
  66. GRB071122: Gemini Absorption redshift
  67. GRB 071122: P60 Optical Afterglow Candidate
  68. GRB 071122: ROTSE-III Optical Limits
  69. GRB 071122: Swift detection of a burst
  70. GRB 071118: P60 Observations
  71. GRB071118 MITSuME OAO optical observation
  72. GRB 071118: Observations from OSN
  73. GRB 071117: VLT observations and probable redshift
  74. Swift/UVOT observations of GRB071118
  75. GRB 071117: Swift-XRT revised position
  76. Konus-Wind and Konus-A observations of GRB 071117
  77. Swift XRT follow-up observations of GRB071008
  78. Swift/UVOT upper limits for GRB 071117
  79. GRB071118: Swift XRT refined analysis
  80. GRB 071117: Gemini Optical Afterglow Discovery
  81. GRB 071118, Swift-BAT refined analysis
  82. GRB 071117: TAROT La Silla observatory optical observations
  83. GRB 071112B: Gemini Image Differencing
  84. GRB 071118: Swift detection of a burst
  85. GRB 071117: Gemini Observations
  86. GRB 071117: Las Campanas optical observations
  87. GRB 071117: Swift-XRT refined analysis
  88. GRB 071117, Swift-BAT refined analysis
  89. VLT FORS2 observations of short hard GRB071112B
  90. GRB 071117: Swift/XRT position
  91. GRB 071117: Initial Swift/UVOT observations
  92. GRB 071117: Swift detection of a bright burst
  93. Swift detection of MXB 0656-072
  94. VLA radio upper limit on GRB 071112C
  95. ATCA radio observations of short hard burst GRB 071112B
  96. GRB 071112C: Optical and NIR data observed with KANATA
  97. Correction to the Swift-BAT Transient Identification (trigger=296683)
  98. GRB 071112C: WSRT Radio Observations
  99. GRB071112C: Errata of MITSuME Ic band photometry
  100. GRB 071112C: optical observation

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