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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"

5833 results found.

  1. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  2. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  3. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  4. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  5. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  6. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  7. Fermi trigger No 602817262: Global MASTER-Net observations report
  8. GRB 200205B: Swift detection of a burst with optical counterpart
  9. GRB200120A: SRG/eROSITA discovery of X-ray afterglow
  10. GRB 200205A: Swift detection of a burst with a possible UV counterpart
  11. Fermi trigger No 602455182: Global MASTER-Net observations report
  12. GRB 200131A: Swift detection of a burst with an optical counterpart
  13. Konus-Wind observation of GRB 200130B
  14. IPN triangulation of GRB 200130B
  15. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  16. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  17. GRB 200130B: BALROG localization (Fermi Trigger 602071201 / GRB 200130417)
  18. GRB 200130B: Fermi GBM Final Real-time Localization
  19. LIGO/Virgo S200129m: Global MASTER-Net observations report
  20. GRB 200129A: Fermi GBM Final Real-time Localization
  21. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  22. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  23. Fermi-LAT-ANTARES coincidence
  24. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  25. GRB 200127A: AbAO optical upper limit
  26. Fermi trigger No 601729856: Global MASTER-Net observations report
  27. Fermi trigger No 601677816: Global MASTER-Net observations report
  28. GRB 200125A: Swift detection of a burst
  29. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  30. Fermi trigger No 601363105: Global MASTER-Net observations report
  31. GRB 191031D: XMM-Newton upper limit
  32. LIGO/VIRGO S200115j: No obvious candidates from Pan-STARRS2 observations
  33. IceCube 200117A: No significant detection in HAWC
  34. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  35. LIGO/Virgo S200105ae: More candidates from the Zwicky Transient Facility
  36. LIGO/Virgo S200114f: More candidates from the Zwicky Transient Facility
  37. IceCube Alert 200117.46: Global MASTER-Net observations report
  38. LIGO/Virgo S200112r : No significant candidates in TAROT - FRAM - GRANDMA observations.
  39. LIGO/Virgo S200115j: No neutrino candidates at Pierre Auger Observatory
  40. LIGO/Virgo S200115j: no counterpart candidate in SVOM/GWAC observations
  41. Baksan Neutrino Observatory Alert 200116.21: Global MASTER-Net observations report
  42. IPN triangulation of GRB 200111A
  43. LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
  44. LIGO/Virgo S200114f: No counterpart in targeted WHT/ACAM imaging
  45. LIGO/Virgo S200115j: INTEGRAL was inactive at the time of the event
  46. LIGO/Virgo S200115j : no neutrino counterpart candidate in ANTARES search
  47. GRB 200114A: DDOTI/OAN optical observations report
  48. LIGO/Virgo S200114f: No Counterparts in DDOTI/OAN Optical Observations
  49. LIGO/Virgo S200114f: upper limits from AGILE-GRID observations
  50. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  51. LIGO/Virgo S200114f: Identification of a GW unmodeled transient candidate
  52. Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034
  53. IceCube 200109A: No significant detection in HAWC
  54. Fermi-LAT ANTARES coincidence: No significant detection in HAWC
  55. Fermi trigger No 600448273: Global MASTER-Net observations report
  56. IceCube-200107A: Upper limits from a search for additional neutrino events in IceCube
  57. IceCube-200109A: INTEGRAL was inactive at the time of the event
  58. IceCube-200109A: IceCube observation of a high-energy neutrino candidate event
  59. IceCube Alert 200109.99: Global MASTER-Net observations report
  60. IceCube Alert 200109.99: Global MASTER-Net observations report
  61. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  62. Fermi-LAT ANTARES coincidence /ANTARES alert 200108.39: MASTER alert and inspect observation
  63. Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  64. Fermi trigger No 600227156: Global MASTER-Net observations report
  65. Swift GRB200109.07: Global MASTER-Net observations report
  66. GRB 200109A: Swift detection of a burst
  67. Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
  68. Fermi-LAT ANTARES coincidence
  69. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  70. IceCube-200107A: No significant detection in HAWC
  71. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  72. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  73. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  74. Fermi trigger No 599761015: Global MASTER-Net observations report
  75. IceCube Alert 200101.46: Global MASTER-Net observations report
  76. Fermi trigger No 599603971: Global MASTER-Net observations report
  77. GRB 191228A: Mondy optical upper limit
  78. IPN triangulation of GRB 191227B (short)
  79. LIGO/Virgo S191225aq: Global MASTER-Net observations report
  80. LIGO/Virgo S191205ah: MASTER OT detection
  81. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  82. GRB 191221B: Swift/UVOT Detection
  83. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  84. GRB 191221B: ALMA detection
  85. GRB 191221B: Swift-BAT refined analysis
  86. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  87. GRB 191221B: Enhanced Swift-XRT position
  88. Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
  89. GRB 191221B: Swift detection of a burst and a very bright optical candidate
  90. LIGO/Virgo S191216ap: MASTER optical observation
  91. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  92. LIGO/Virgo S191213g : SAO 1-m optical observation of AT2019wxt (PS19hgw)
  93. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  94. LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
  95. LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
  96. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  97. LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
  98. Fermi-LAT Gamma-ray Observations of IceCube-191215A
  99. IceCube-191215A: Upper limits from a search for additional neutrino events in IceCube
  100. UKIRT photometry of ZTF19acyldun/AT 2019wrt

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