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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"

28041 results found.

  1. IceCube-191122A: No significant detection in HAWC
  2. IceCube-191122A: Upper limits from a search for additional neutrino events in IceCube
  3. Fermi-LAT Gamma-ray Observations of IceCube-191122A
  4. GRB 191123A: Swift/UVOT further analysis
  5. GRB 191123A: Swift-BAT refined analysis
  6. GRB 191123A: Swift-XRT refined Analysis
  7. GRB 191123A: Enhanced Swift-XRT position
  8. GRB 191123A: iTelescope optical upper limits
  9. GRB 191123A: Swift/UVOT detection
  10. GRB 191123A: Swift detection of a burst with an optical counterpart
  11. GRB 191118A: Insight-HXMT/HE detection
  12. GRB 191122A: Swift/UVOT Upper Limits
  13. GRB 191122A: Swift-BAT refined analysis
  14. GRB 191122A: Swift-XRT refined Analysis
  15. GRB 191122A: Enhanced Swift-XRT position
  16. GRB 191122A: Swift detection of a burst
  17. IceCube-191119A: No significant detection in HAWC
  18. IceCube-191119A: No neutrino counterpart candidates in ANTARES search
  19. IceCube-191119A: Upper limits from a search for additional neutrino events in IceCube
  20. Fermi-LAT Gamma-ray Observations of IceCube-191119A
  21. IceCube-191119A - No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. GRB 191118A: BALROG localization (Fermi Trigger 595807926 / GRB 191118925)
  23. Swift Trigger 937114 is not an astrophysical source
  24. LIGO/Virgo S191110af: Retraction of GW unmodeled transient candidate
  25. LIGO/Virgo S191110af: Upper limits from KM3NeT MeV neutrino search.
  26. LIGO/Virgo S191110af: Upper limits from Konus-Wind observations
  27. GRB 191111A: Insight-HXMT/HE detection
  28. LIGO/Virgo S191105e: Updated Sky Localization
  29. LIGO/Virgo S191110af: Potential pulsar counterparts
  30. Konus-Wind observation of the recent SGR 1935+2154 activity
  31. LIGO/Virgo S191110af: Swift XRT observations, no secure afterglow found
  32. LIGO/Virgo S191110af: Upper limits from CALET observations.
  33. LIGO/Virgo S191110af: Upper limits from IceCube MeV neutrino searches
  34. LIGO/Virgo S191110af: no counterpart candidates in the Swift/BAT observations
  35. GRB 191111B: BALROG localization (Fermi Trigger 595170435 / GRB 191111547)
  36. LIGO/Virgo S191110af: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  37. LIGO/Virgo S191110af: No neutrino counterpart candidate in ANTARES search
  38. LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations
  39. LIGO/Virgo S191110af: upper limits from AGILE/MCAL observations
  40. LIGO/Virgo S191110af: Evryscope observation report, no counterpart candidates
  41. LIGO/Virgo S191110af: No counterpart candidates in INTEGRAL SPI-ACS, prompt observation
  42. LIGO/Virgo S191110af: Coverage and upper limits from MAXI/GSC observations
  43. LIGO/Virgo S191110af: Identification of a GW unmodeled transient candidate
  44. LIGO/Virgo S191110af: Upper limits from IceCube neutrino searches
  45. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  46. LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
  47. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  48. LIGO/Virgo S191105e: Upper limits from Insight-HXMT/HE observations
  49. LIGO/Virgo S191109d: AstroSat CZTI upper limits
  50. LIGO/Virgo S191109d: no counterpart candidates in the Swift/BAT observations
  51. LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
  52. LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:
  53. LIGO/Virgo S191109d: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
  54. LIGO/Virgo S191109d: upper limits from AGILE/MCAL observations
  55. LIGO/Virgo S191109d: Upper limits from Fermi-GBM Observations
  56. LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
  57. LIGO/Virgo S191109d: Upper limits from IceCube neutrino searches
  58. LIGO/Virgo S191109d: Identification of a GW compact binary merger candidate
  59. GRB 191106A: Swift/UVOT Upper Limits
  60. GRB 191106A: Swift-BAT refined analysis
  61. ZTF19abvizsw: Upper limits from Konus-Wind observations
  62. LIGO/Virgo S191105e: AstroSat CZTI upper limits
  63. LIGO/Virgo S191105e: No counterpart candidates in Fermi-LAT observations
  64. LIGO/Virgo S191105e: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo S191105e: no counterpart candidates in the Swift/BAT observations
  66. GRB 191106A: NOT optical upper limit
  67. GRB 191106A: Swift-XRT refined Analysis
  68. LIGO/Virgo S191105e : no neutrino counterpart candidate in ANTARES search
  69. LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
  70. LIGO/Virgo S191105e: No counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  71. LIGO/Virgo S191105e: upper limits from AGILE/GRID observations
  72. LIGO/Virgo S191105e: Upper limits from Fermi-GBM Observations
  73. LIGO/Virgo S191105e: Global MASTER-Net observations report
  74. LIGO/Virgo S191105e: upper limits from AGILE/MCAL observations
  75. LIGO/Virgo S191105e: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo S191105e: Upper limits from IceCube neutrino searches
  77. GRB 191106A: Mondy optical upper limit
  78. GRB 191106A: Swift detection of a burst
  79. GRB191016A GROND observations
  80. Trigger 933276: Swift detection of further activity from SGR 1935+2154
  81. Swift GRB191105.01: Global MASTER-Net OT detection
  82. GRB 191101A: Swift-BAT refined analysis
  83. GRB 191101A: Swift/UVOT Upper Limits
  84. SGR 1935+2154: Swift-BAT refined analysis
  85. GRB 191104C: BALROG localization (Fermi Trigger 594557071 / GRB 191104448)
  86. GRB 191031E: Insight-HXMT/HE detection
  87. GRB 191031D: Gemini optical upper limit
  88. GRB 191031C: Insight-HXMT/HE detection
  89. GRB 191101A: iTelescope optical limit
  90. GRB 191101A: Swift-XRT refined Analysis
  91. GRB 191101A: VIRT Optical Upper Limits
  92. GRB 191101A: Enhanced Swift-XRT position
  93. Fermi trigger No 594227699: Global MASTER-Net observations report
  94. GRB 191101B: Fermi GBM Final Real-time Localization
  95. GRB 191101A: Swift detection of a burst
  96. GRB 191031D: MMT Binospec Optical Upper Limit
  97. GRB 191031D: Swift-BAT refined analysis
  98. GRB 191031C: Swift-BAT refined analysis
  99. GRB 191031A: Swift-BAT refined analysis
  100. GRB 191031C: Swift-XRT refined Analysis

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