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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"

5835 results found.

  1. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  2. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  3. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  4. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  5. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  6. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  7. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  8. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  9. Fermi trigger No 602817262: Global MASTER-Net observations report
  10. GRB 200205B: Swift detection of a burst with optical counterpart
  11. GRB200120A: SRG/eROSITA discovery of X-ray afterglow
  12. GRB 200205A: Swift detection of a burst with a possible UV counterpart
  13. Fermi trigger No 602455182: Global MASTER-Net observations report
  14. GRB 200131A: Swift detection of a burst with an optical counterpart
  15. Konus-Wind observation of GRB 200130B
  16. IPN triangulation of GRB 200130B
  17. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  18. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  19. GRB 200130B: BALROG localization (Fermi Trigger 602071201 / GRB 200130417)
  20. GRB 200130B: Fermi GBM Final Real-time Localization
  21. LIGO/Virgo S200129m: Global MASTER-Net observations report
  22. GRB 200129A: Fermi GBM Final Real-time Localization
  23. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  24. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  25. Fermi-LAT-ANTARES coincidence
  26. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  27. GRB 200127A: AbAO optical upper limit
  28. Fermi trigger No 601729856: Global MASTER-Net observations report
  29. Fermi trigger No 601677816: Global MASTER-Net observations report
  30. GRB 200125A: Swift detection of a burst
  31. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  32. Fermi trigger No 601363105: Global MASTER-Net observations report
  33. GRB 191031D: XMM-Newton upper limit
  34. LIGO/VIRGO S200115j: No obvious candidates from Pan-STARRS2 observations
  35. IceCube 200117A: No significant detection in HAWC
  36. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  37. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  38. LIGO/Virgo S200114f: More candidates from the Zwicky Transient Facility
  39. IceCube Alert 200117.46: Global MASTER-Net observations report
  40. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  41. LIGO/Virgo S200115j: No neutrino candidates at Pierre Auger Observatory
  42. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  43. Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
  44. IPN triangulation of GRB 200111A
  45. LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
  46. LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
  47. LIGO/Virgo S200115j: INTEGRAL was inactive at the time of the event
  48. LIGO/Virgo S200115j : no neutrino counterpart candidate in ANTARES search
  49. GRB 200114A: DDOTI/OAN optical observations report
  50. LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
  51. LIGO/Virgo S200114f: upper limits from AGILE-GRID observations
  52. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  53. LIGO/Virgo S200114f: Identification of a GW unmodeled transient candidate
  54. Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034
  55. IceCube 200109A: No significant detection in HAWC
  56. Fermi-LAT ANTARES coincidence: No significant detection in HAWC
  57. Fermi trigger No 600448273: Global MASTER-Net observations report
  58. IceCube-200107A: Upper limits from a search for additional neutrino events in IceCube
  59. IceCube-200109A: INTEGRAL was inactive at the time of the event
  60. IceCube-200109A: IceCube observation of a high-energy neutrino candidate event
  61. IceCube Alert 200109.99: Global MASTER-Net observations report
  62. IceCube Alert 200109.99: Global MASTER-Net observations report
  63. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  64. Fermi-LAT ANTARES coincidence /ANTARES alert 200108.39: MASTER alert and inspect observation
  65. Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  66. Fermi trigger No 600227156: Global MASTER-Net observations report
  67. Swift GRB200109.07: Global MASTER-Net observations report
  68. GRB 200109A: Swift detection of a burst
  69. Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
  70. Fermi-LAT ANTARES coincidence
  71. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  72. IceCube-200107A: No significant detection in HAWC
  73. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  74. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  75. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  76. Fermi trigger No 599761015: Global MASTER-Net observations report
  77. IceCube Alert 200101.46: Global MASTER-Net observations report
  78. Fermi trigger No 599603971: Global MASTER-Net observations report
  79. GRB 191228A: Mondy optical upper limit
  80. IPN triangulation of GRB 191227B (short)
  81. LIGO/Virgo S191225aq: Global MASTER-Net observations report
  82. LIGO/Virgo S191205ah: MASTER OT detection
  83. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  84. GRB 191221B: Swift/UVOT Detection
  85. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  86. GRB 191221B: ALMA detection
  87. GRB 191221B: Swift-BAT refined analysis
  88. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  89. GRB 191221B: Enhanced Swift-XRT position
  90. Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
  91. GRB 191221B: Swift detection of a burst and a very bright optical candidate
  92. LIGO/Virgo S191216ap: MASTER optical observation
  93. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  94. LIGO/Virgo S191213g : SAO 1-m optical observation of AT2019wxt (PS19hgw)
  95. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  96. LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
  97. LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
  98. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  99. LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
  100. Fermi-LAT Gamma-ray Observations of IceCube-191215A

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