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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"

28048 results found.

  1. MAXI GRB200205.29: Global MASTER-Net observations report
  2. GRB 200205A: Swift detection of a burst with a possible UV counterpart
  3. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  4. LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
  5. GRB 200131A: Further RATIR Optical Observations
  6. AMON IceCube-HAWC_200202A : No neutrino counterpart seen with ANTARES
  7. GRB 200131A: Swift-BAT refined analysis
  8. GRB 200131A: ISON-Castelgrande optical observations
  9. GRB 200131A: CDK700 optical observations
  10. GRB 200131A: Swift/UVOT Detection
  11. GRB 200131A: Swift-XRT refined Analysis
  12. GRB 200131A: VIRT optical transient detection
  13. GRB 200131A: LCO Optical Detection
  14. GRB 200131A: RATIR Optical Observations
  15. GRB 200131A: Enhanced Swift-XRT position
  16. GRB 200201A: Fermi GBM Final Real-time Localization
  17. GRB 200131A: Swift detection of a burst with an optical counterpart
  18. Konus-Wind observation of GRB 200130B
  19. IPN triangulation of GRB 200130B
  20. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  21. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  22. GRB 200130B: BALROG localization (Fermi Trigger 602071201 / GRB 200130417)
  23. LIGO/Virgo S200129m: Upper limits from CALET observations.
  24. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  25. GRB 200127A: Swift-BAT refined analysis
  26. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  27. LIGO/Virgo S200129m: Not observable by Fermi-GBM
  28. Konus-Wind observation of GRB 200125A
  29. LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
  30. LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
  31. LIGO/Virgo S200129m: upper limits from AGILE/MCAL observations
  32. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  33. LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  34. LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
  35. LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  37. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  38. Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
  39. GRB 200127A: Swift/UVOT Upper Limits
  40. LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
  41. Fermi-LAT-ANTARES coincidence
  42. GRB 200127A: Mondy optical upper limit
  43. GRB200127A: Nordic Optical telecope optical upper limit
  44. LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
  45. GRB 200125B: DDOTI/OAN optical observations report
  46. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  47. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  48. LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
  49. LIGO/Virgo S200128d: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo S200128d: Upper limits from IceCube neutrino searches
  51. GRB 200127A: Nanshan-0.6m optical upper limit
  52. GRB 200127A: Enhanced Swift-XRT position
  53. GRB 200127A: Swift-XRT refined Analysis
  54. GRB 200127A: AbAO optical upper limit
  55. GRB 200125A: Swift-BAT refined analysis
  56. GRB 200127A: Swift detection of a burst
  57. GRB 200125A: Further Swift-XRT observations
  58. GRB 200125B: Fermi GBM observations
  59. GRB 200125A: Swift/UVOT Upper Limits
  60. GRB 200125A: Further RATIR Optical Observations and Confirmation of Fading
  61. GRB 200125A: AbAO optical upper limit
  62. GRB 200125B: Insight-HXMT/HE detection
  63. GRB 200125A: TNG detection of a NIR counterpart candidate
  64. Fermi trigger No 601677816: Global MASTER-Net observations report
  65. Correction to GRB 200125A: Swift-XRT refined analysis
  66. GRB 200125A: Swift-XRT refined Analysis
  67. GRB 200125A: Nanshan-0.6m optical upper limit
  68. GRB 200125A: RATIR Optical Observations
  69. GRB 200125B: BALROG localization (Fermi Trigger 601677816 / GRB 200125864)
  70. GRB 200125A: Enhanced Swift-XRT position
  71. GRB 200122B: Insight-HXMT/HE detection
  72. GRB 200125A: Swift detection of a burst
  73. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  74. GRB 200115A: Assy optical observations
  75. GRB 200122A: Mondy optical upper limit
  76. LIGO/Virgo S191222n: AstroSat CZTI upper limits
  77. LIGO/Virgo S200112r: AstroSat CZTI upper limits
  78. LIGO/Virgo S200114f: AstroSat CZTI upper limits
  79. LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
  80. GRB 200122A: RATIR Optical Observations
  81. GRB 200122A: Swift-BAT refined analysis
  82. GRB 200122A: Xinglong-2.16m optical upper limit
  83. GRB 200122A: Swift/UVOT Upper Limits
  84. IPN Triangulation of GRB 200120A
  85. LIGO/Virgo S200115j: Further Swift-XRT sources
  86. GRB 200122A: GOTO non-detection of optical afterglow
  87. GRB 200122A: Swift-XRT refined Analysis
  88. Fermi-LAT Gamma-ray Observations of IceCube-200120A
  89. LIGO/Virgo S200115j: Upper limits from Konus-Wind observations
  90. LIGO/Virgo S200114f: Upper limits from Konus-Wind observations
  91. LIGO/Virgo S200112r: Upper limits from Konus-Wind observations
  92. GRB 200122A: Enhanced Swift-XRT position
  93. GRB 200122A: Swift detection of a burst
  94. Fermi trigger No 601254300: Global MASTER-Net observations report
  95. GRB 191031D: XMM-Newton upper limit
  96. GRB 200120A: Insight-HXMT/HE detection
  97. IceCube-200120A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  98. LIGO/Virgo S200105ae: Upper limits from Konus-Wind observations
  99. LIGO/Virgo S191222n: Upper limits from Konus-Wind observations
  100. LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations

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