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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"

18334 results found.

  1. GRB 070911: Swift XRT refined analysis
  2. GRB 070809: Confirmation of optical transient
  3. Candidate Orphan GRB Optical Transient in IC 4779
  4. Las Campanas observations of possible TAROT GRB transient near IC
  5. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  6. GRB 070824 - Combined SuperAGILE/IPN Localization
  7. GRB 070731: Swift/UVOT Upper Limit
  8. GRB 070805: UVOT afterglow candidate retraction
  9. GRB 070810B : Faulkes Telescope South Observations
  10. GRB 070810A: Continued Keck Imaging
  11. GRB 070810B: Keck spectroscopy of possible host galaxies
  12. GRB070810B: Swift/UVOT Upper Limits
  13. GRB 070810B: Xinglong TNT optical Upper Limit
  14. GRB070810B: Optical observations with KANATA
  15. GRB 070809: Swift/UVOT Upper Limits
  16. VLA upper limit on the short hard burst GRB 070729
  17. No radio detection in superAGILE burst 070724B
  18. GRB 070809: Keck Imaging
  19. GRB 070810: enhanced Swift-XRT position
  20. GRB 070810: Swift/UVOT Optical Counterpart
  21. GRB 070808: Swift/UVOT upper limits
  22. GRB 070809: Swift detection of a short burst
  23. GRB 070808 : Faulkes Telescope South Observations
  24. GCN Swift XRT update position notices and enhanced position circulars
  25. GRB 070808: Swift XRT refined analysis
  26. GRB 070808: Xinglong TNT optical Upper Limit
  27. GRB070808: Optical observations with KANATA
  28. GRB070808 - SDSS Pre-Burst Observations
  29. GRB 070808: ROTSE-III Optical Limits
  30. GRB070805 XRT and UVOT afterglow candidate
  31. GRB070612A: Radio upper limit from GMRT
  32. Swift/UVOT observations of GRB070805
  33. UVOT observations of SAXJ1810.8-2609
  34. Swift detection of a outburst from SAX J1810.8-2609
  35. VLA non-detection of GRB 070721B
  36. GRB 070802: REM optical observations
  37. GRB 070802: Swift-XRT refined analysis
  38. GRB070802: Swift/UVOT upper limits
  39. GRB 070802: V-band detection of the candidate afterglow
  40. GRB 070802: GROND J band candidate
  41. Swift/UVOT detection of GRB070714B
  42. VLA upper limit on short hard burst GRB 070714B
  43. GRB070729: Swift/UVOT upper limits
  44. GRB 070724B: P60 Observations
  45. GRB 070724B: Swift/UVOT Upper limits
  46. GRB 070724B: Swift-XRT afterglow likely candidate
  47. GRB 070721A: optical observations
  48. GRB 070724A: further VLT observations
  49. Four radio sources in Swift-XRT error box of GRB 070724
  50. GRB 070724: P60 and Gemini Observations
  51. GRB 060814 - Keck host detection and redshift
  52. Swift/UVOT refined analysis of GRB070724
  53. GRB 070724: Swift-XRT Team refined analysis
  54. GRB 070721B: further observations and analysis
  55. GRB 070724: Swift detection of a burst
  56. GRB 070714B: Keck observations
  57. Swift/UVOT Observations of GRB070721A
  58. GRB 070721B : Faulkes Telescope South observations
  59. GRB 070721A : Faulkes Telescope South optical limit
  60. GRB 070721A: Swift/XRT refined analysis
  61. GRB070721B: A bright UVOT candidate
  62. GRB070714B: TNG NIR observations
  63. GRB 070714A: Swift/UVOT Upper limits
  64. GRB 070714B: Swift/UVOT Upper Limits
  65. GRB 070714B: Swift-BAT spectral lag for the SHB
  66. GRB 070714B: confirmation of optical afterglow
  67. GRB 070616: No Evidence for I Band Afterglow
  68. GRB 070714A: Swift XRT refined analysis
  69. GRB070714B: Swift-XRT refined analysis
  70. GRB 070714 : Liverpool Telescope optical counterpart ?
  71. GRB 070714: Swift detection of a bright burst, possibly short
  72. GRB 070704: RTT150 optical observations
  73. GRB 070707: optical afterglow
  74. Swift/UVOT Observations of GRB070707
  75. Swift XRT observation of GRB 070707
  76. GRB 070707: VLT observations
  77. GRB070704: FAVOR optical observations
  78. GRB 070704 : Liverpool Telescope Observations
  79. GRB 070611: VLT observations
  80. VLA detection of GRB 070612A in C Band
  81. GRB 070704: Swift-XRT refined analysis
  82. Swift/UVOT Observations of GRB070704
  83. GRB 070704: Correction to GCN Circ 6594
  84. GRB 070704: Swift detection of a burst
  85. GRB 070628 Swift-UVOT Refined Analysis
  86. GRB 070628: NIR detection of afterglow
  87. GRB 070628: TAROT La Silla observatory optical observations
  88. GRB 070616 : WIDGET simultaneous optical observations
  89. GRB070621: RTT150 optical observations
  90. GRB 070621: VLT optical observations
  91. GRB 070621: Swift/UVOT Upper Limits
  92. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  93. GRB 070621: Gemini South optical imaging
  94. GRB 070621: UVOT-enhanced XRT position
  95. Observations of GRB070612A at Calar Alto
  96. GRB 070621: NOT observations
  97. GRB 070621: TAROT Calern observatory optical observations
  98. GRB 070621: Watcher Observations
  99. GRB 070621: Swift detection of a burst
  100. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz

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