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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"

3763 results found.

  1. Swift GRB191227.07: Global MASTER-Net observations report
  2. Swift GRB191226.02: Global MASTER-Net observations report
  3. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  4. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  5. GRB 191221B: iTelescope optical observations
  6. LIGO/Virgo S191216ap: No significant candidates found in Pan-STARRS observations
  7. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  8. GRB 191221B: Swift detection of a burst and a very bright optical candidate
  9. GRB 191221A: Fermi GBM Final Real-time Localization
  10. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  11. Konus-Wind observation of GRB 191218A
  12. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  13. LIGO/Virgo S191216ap: No transient candidates in CALET observations
  14. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  15. LIGO/Virgo S191215w: No transient candidates in CALET observations
  16. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  17. LIGO/Virgo S191213g: No transient candidates in CALET observations
  18. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  19. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  20. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
  21. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  22. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  23. LIGO/Virgo S191204r: No transient candidates in CALET observations
  24. IceCube Alert 191204.95: Global MASTER-Net observations report
  25. Fermi trigger No 597049044: Global MASTER-Net observations report
  26. LIGO/Virgo S191129u: No transient candidates in CALET observations
  27. Fermi trigger No 596808579: Global MASTER-Net observations report
  28. Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
  29. Fermi trigger No 596387570: Global MASTER-Net observations report
  30. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  31. LIGO/Virgo S191124be: Global MASTER-Net observations report
  32. IceCube-191122A: Global MASTER-Net observations report
  33. IceCube-191119A: No neutrino counterpart candidates in ANTARES search
  34. GRB 191117A: Fermi GBM Final Real-time Localization
  35. LIGO/Virgo S191110af: Coverage and upper limits from MAXI/GSC observations
  36. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  37. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  38. LIGO/Virgo S191105e: AstroSat CZTI upper limits
  39. LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
  40. GRB 191106A: MASTER optical observation
  41. Fermi trigger No 594592184: Global MASTER-Net observations report
  42. Fermi trigger No 594557071: Global MASTER-Net observations report
  43. GRB 191101B: Fermi GBM Final Real-time Localization
  44. GRB 191029A: Swift-XRT refined Analysis
  45. GRB 191028B: MASTER optical observation
  46. IPN triangulation of GRB 191025B (short)
  47. GRB 191028B: BALROG localization (Fermi Trigger 593964489 / GRB 191028589)
  48. GRB 191028B: Fermi GBM Final Real-time Localization
  49. Fermi GBM trigger 593931926/191028212 is not a GRB
  50. GRB 191028A: Fermi GBM Final Real-time Localization
  51. Fermi trigger No 593176520: Global MASTER-Net observations report
  52. Fermi trigger No 592211224: Global MASTER-Net observations report
  53. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  54. GRB 190928A: AstroSat CZTI detection
  55. Swift GRB191004.9: Global MASTER-Net OT detection
  56. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
  57. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
  58. LIGO/Virgo S190930t: HCT observations of ZTF19acbpsuf
  59. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  60. Fermi trigger No 591604915: Global MASTER-Net observations report
  61. LIGO/Virgo S190930t: Upper limits from CALET observations.
  62. LIGO/Virgo S190930s: Upper limits from CALET observations.
  63. GRB 190928A: CALET Gamma-Ray Burst Monitor detection
  64. Fermi trigger No 591391412: Global MASTER-Net observations report
  65. GRB 190928A: AGILE/MCAL detection of a burst
  66. Baksan Neutrino Observatory Alert 190928.37: Global MASTER-Net observations report
  67. Fermi trigger No 591321287: Global MASTER-Net observations report
  68. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  69. LIGO/Virgo S190923y: Upper limits from CALET observations.
  70. IceCube-190922B - HAWC follow-up
  71. LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
  72. LIGO/Virgo S190814bv: HST and ALMA observations of the host galaxy of ASKAP J005547-270433 / AT 2019osy
  73. Fermi trigger No 590621700: Global MASTER-Net observations report
  74. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  75. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  76. GRB 190828B: AstroSat CZTI detection
  77. LIGO/Virgo S190915ak: No transient candidates in CALET observations
  78. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  79. GRB 190828C: AstroSat CZTI detection
  80. LIGO/Virgo S190910d: MASTER previous detection of Gaia19eba/AT2019qam
  81. LIGO/Virgo S190910h: Upper limits from CALET observations.
  82. LIGO/Virgo S190910d: No transient candidates in CALET observations.
  83. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  84. LIGO/Virgo S190910d: AstroSat CZTI upper limits
  85. LIGO/Virgo S190910d Global MASTER-Net observations report
  86. LIGO/Virgo S190814bv: VLA/JAGWAR monitoring of the 50% containment region
  87. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  88. ZTF19abvizsw/AT2019pim, search for GRB in SPI-ACS/INTEGRAL data
  89. Fermi trigger No 589561732 Global MASTER-Net observations report
  90. GRB 190905A: Fermi GBM Final Real-time Localization
  91. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  92. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  93. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  94. LIGO/Virgo S190901ap: Upper limits from CALET observations.
  95. Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
  96. LIGO/Virgo S190901ap : SVOM/GWAC-F60A observation of transient ZTFabvizsw
  97. LIGO/Virgo S190828l: no counterpart candidate in the SVOM/GWAC observations
  98. LIGO/Virgo S190828j: no counterpart candidate in the SVOM/GWAC observations
  99. Fermi trigger No 589065714 Global MASTER-Net observations report
  100. LIGO/Virgo S190814bv : No significant candidates in TAROT-GRANDMA observations

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