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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"

5082 results found.

  1. Swift detection of 4U 1700+24 (= V934 Her)
  2. GRB 141202A: Swift XRT observations
  3. IPN Triangulation of GRB 141202A (short/hard)
  4. IPN Triangulation of GRB 141121A (initial episode)
  5. GRB 141121A: SPI-ACS/INTEGRAL observations
  6. IPN Triangulation of GRB 141125A (short/hard)
  7. GRB141124A: MASTER Detection of New Flare of QSO NVSS J075043+790917 During the Fermi Error Box inspection
  8. GRB 141121A: MAXI/GSC detection
  9. GRB141121A: BOOTES-2/TELMA upper limit
  10. GRB 141121A: Swift detection of a burst
  11. IPN Triangulation of GRB 141118A
  12. Swift Trigger 618134 is not an astrophysical event
  13. GRB 141104A: Swift-XRT observations
  14. Konus-Wind observation of GRB 141104A
  15. IPN Triangulation of GRB 141104A (long/very bright)
  16. GRB 141031B: MITSuME Ishigakijima upper limits
  17. GRB 141031B: MASTER early optical observations
  18. GRB 141029B: Fermi GBM detection
  19. GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
  20. GRB 141026A: SAO RAS Zeiss-1000 observations
  21. GRB141026A: Deep P200 optical imaging
  22. GRB 140930B: GROND observations
  23. Swift detection of outburst from 4U 1700+24
  24. GRB 140909A: Confirmation of the Swift-XRT afterglow
  25. GRB 140907A: Mondy optical observations
  26. GRB 140909A: Swift-XRT observations
  27. GRB 140907A: MASTER optical observations
  28. GRB 140907A : Virtual Telescope optical observations
  29. GRB140907A: Swift UVOT detection
  30. GRB 140907A : Optical observations from Nanshan
  31. GRB 140901B: Swift XRT observation
  32. GRB 140903A: ISON-Kislovodsk observations
  33. GRB 140903A: MAXI/GSC upper limit
  34. GRB140903A: Discovery Channel Telescope Optical Detection
  35. GRB 140829A: iPTF optical observations
  36. GRB 140824B: Swift observations
  37. Swift detection of SAX J1712.6-3739
  38. GRB 140817A: Swift detection of a burst
  39. GRB 140814A: Swift-XRT and UVOT observations
  40. GRB 140814A: Swift-XRT and UVOT observations
  41. GRB 140814A: MAXI/GSC detection
  42. GRB140809A: Fermi GBM observation
  43. Swift trigger 609139 is probably 4U 1850-03
  44. GRB 140801A (FERMI trigger 428612396): MASTER brigth OT discovery
  45. GRB 140730A: Prompt enhanced Swift-XRT position
  46. GRB 140729A: Swift-XRT and UVOT observations
  47. GRB 140723A: LCO-Sutherland optical candidate
  48. Konus-Wind observation of GRB 140721A
  49. IPN Triangulation of GRB 140721A
  50. GRB 140721A: Fermi GBM detection
  51. GRB 140719A: Swift detection of a burst
  52. Swift Trigger 604111 is not a GRB
  53. GRB 140706A: Swift/UVOT Detection
  54. GRB 140706A: Swift-BAT refined analysis
  55. GRB 140703A: AAO optical observations
  56. Pre-discovery observations of SGR 1935+2154 in Swift archival data
  57. GRB 140706A: Enhanced Swift-XRT position
  58. GRB 140706A: Swift detection of a burst with an optical counterpart
  59. GRB 140703A: CARMA 3mm detection
  60. GRB 140703A: P60 observations of a red, slowly-fading afterglow
  61. GRB 140703A: Monte Agliale Observatory optical observations
  62. GRB 140703A: MASTER optical observations
  63. GRB 140629A: SAO RAS monitoring
  64. GRB 140621A: Swift-XRT observations
  65. GRB 140619B: Swift-XRT observations
  66. GRB 140610A: TShAO optical upper limit
  67. Konus-Wind observation of GRB 140611A
  68. IPN Triangulation of GRB 140611A (short/hard)
  69. Konus-Wind observation of GRB 140606B
  70. IPN Triangulation of GRB 140606B
  71. GRB 140606B: Fermi GBM detection
  72. Fermi423717114: iPTF optical transient candidates
  73. GRB 140529A: Swift-XRT afterglow detection.
  74. Konus-Wind observation of GRB 140523A
  75. IPN Triangulation of GRB 140523A
  76. GRB 140523A: Fermi-LAT detection
  77. GRB 140523A: Fermi GBM detection
  78. GRB 140521A: AROMA-N Optical Observation
  79. GRB 140515B: MAXI/GSC detection
  80. GRB 140423A: HCT optical observations
  81. GRB 140508A: Mondy upper limit
  82. GRB140512A : GROND observations
  83. GRB 140509A: Swift/UVOT Detection and photo-z
  84. Konus-Wind observation of GRB 140508A
  85. GRB 140509A: Swift detection of a burst with an optical counterpart
  86. GRB 140508A: iPTF optical transient candidate
  87. IPN triangulation of GRB 140508A
  88. GRB 140508A: Fermi GBM detection
  89. GRB 140501A: Fermi GBM detection
  90. GRB 140430A: VATT Optical Observations
  91. DG CVn: optical observations
  92. GRB 140423A: Nishi-Harima NIR Observations
  93. Swift Trigger 596958 is positionally consistent with V* DG CVn/2XMM J133146.4+291635
  94. GRB 140419A, LOAO R-band observations
  95. GRB 140423A: ISON-MN early photometry and correction to the GCN circ. 16143
  96. GRB 140423A: optical afterglow candidate
  97. GRB 140419A: MITSuME Okayama Optical Observation
  98. GRB 140408A: MITSuME Akeno Optical observation
  99. GRB 140406A: Fermi GBM observation
  100. GRB 140402A: Swift-XRT observations

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