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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"

3757 results found.

  1. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  2. GRB 191221B: Swift detection of a burst and a very bright optical candidate
  3. GRB 191221A: Fermi GBM Final Real-time Localization
  4. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  5. Konus-Wind observation of GRB 191218A
  6. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  7. LIGO/Virgo S191216ap: No transient candidates in CALET observations
  8. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  9. LIGO/Virgo S191215w: No transient candidates in CALET observations
  10. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  11. LIGO/Virgo S191213g: No transient candidates in CALET observations
  12. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  13. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  14. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
  15. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  16. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  17. LIGO/Virgo S191204r: No transient candidates in CALET observations
  18. IceCube Alert 191204.95: Global MASTER-Net observations report
  19. Fermi trigger No 597049044: Global MASTER-Net observations report
  20. LIGO/Virgo S191129u: No transient candidates in CALET observations
  21. Fermi trigger No 596808579: Global MASTER-Net observations report
  22. Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
  23. Fermi trigger No 596387570: Global MASTER-Net observations report
  24. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  25. LIGO/Virgo S191124be: Global MASTER-Net observations report
  26. IceCube-191122A: Global MASTER-Net observations report
  27. IceCube-191119A: No neutrino counterpart candidates in ANTARES search
  28. GRB 191117A: Fermi GBM Final Real-time Localization
  29. LIGO/Virgo S191110af: Coverage and upper limits from MAXI/GSC observations
  30. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  31. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  32. LIGO/Virgo S191105e: AstroSat CZTI upper limits
  33. LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
  34. GRB 191106A: MASTER optical observation
  35. Fermi trigger No 594592184: Global MASTER-Net observations report
  36. Fermi trigger No 594557071: Global MASTER-Net observations report
  37. GRB 191101B: Fermi GBM Final Real-time Localization
  38. GRB 191029A: Swift-XRT refined Analysis
  39. GRB 191028B: MASTER optical observation
  40. IPN triangulation of GRB 191025B (short)
  41. GRB 191028B: BALROG localization (Fermi Trigger 593964489 / GRB 191028589)
  42. GRB 191028B: Fermi GBM Final Real-time Localization
  43. Fermi GBM trigger 593931926/191028212 is not a GRB
  44. GRB 191028A: Fermi GBM Final Real-time Localization
  45. Fermi trigger No 593176520: Global MASTER-Net observations report
  46. Fermi trigger No 592211224: Global MASTER-Net observations report
  47. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  48. GRB 190928A: AstroSat CZTI detection
  49. Swift GRB191004.9: Global MASTER-Net OT detection
  50. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
  51. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
  52. LIGO/Virgo S190930t: HCT observations of ZTF19acbpsuf
  53. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  54. Fermi trigger No 591604915: Global MASTER-Net observations report
  55. LIGO/Virgo S190930t: Upper limits from CALET observations.
  56. LIGO/Virgo S190930s: Upper limits from CALET observations.
  57. GRB 190928A: CALET Gamma-Ray Burst Monitor detection
  58. Fermi trigger No 591391412: Global MASTER-Net observations report
  59. GRB 190928A: AGILE/MCAL detection of a burst
  60. Baksan Neutrino Observatory Alert 190928.37: Global MASTER-Net observations report
  61. Fermi trigger No 591321287: Global MASTER-Net observations report
  62. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  63. LIGO/Virgo S190923y: Upper limits from CALET observations.
  64. IceCube-190922B - HAWC follow-up
  65. LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
  66. LIGO/Virgo S190814bv: HST and ALMA observations of the host galaxy of ASKAP J005547-270433 / AT 2019osy
  67. Fermi trigger No 590621700: Global MASTER-Net observations report
  68. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  69. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  70. GRB 190828B: AstroSat CZTI detection
  71. LIGO/Virgo S190915ak: No transient candidates in CALET observations
  72. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  73. GRB 190828C: AstroSat CZTI detection
  74. LIGO/Virgo S190910d: MASTER previous detection of Gaia19eba/AT2019qam
  75. LIGO/Virgo S190910h: Upper limits from CALET observations.
  76. LIGO/Virgo S190910d: No transient candidates in CALET observations.
  77. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  78. LIGO/Virgo S190910d: AstroSat CZTI upper limits
  79. LIGO/Virgo S190910d Global MASTER-Net observations report
  80. LIGO/Virgo S190814bv: VLA/JAGWAR monitoring of the 50% containment region
  81. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  82. ZTF19abvizsw/AT2019pim, search for GRB in SPI-ACS/INTEGRAL data
  83. Fermi trigger No 589561732 Global MASTER-Net observations report
  84. GRB 190905A: Fermi GBM Final Real-time Localization
  85. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  86. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  87. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  88. LIGO/Virgo S190901ap: Upper limits from CALET observations.
  89. Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
  90. LIGO/Virgo S190901ap : SVOM/GWAC-F60A observation of transient ZTFabvizsw
  91. LIGO/Virgo S190828l: no counterpart candidate in the SVOM/GWAC observations
  92. LIGO/Virgo S190828j: no counterpart candidate in the SVOM/GWAC observations
  93. Fermi trigger No 589065714 Global MASTER-Net observations report
  94. LIGO/Virgo S190814bv : No significant candidates in TAROT-GRANDMA observations
  95. LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
  96. LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
  97. LIGO/Virgo S190828j: No Counterparts in DDOTI/OAN Optical Observations
  98. LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
  99. LIGO/Virgo S190814bv: Upper limits from a two-week IceCube search for neutrinos from the direction of ASKAP J005547-270433
  100. Fermi trigger No 588801358 Global MASTER-Net observations report

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