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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"

6098 results found.

  1. GRB 200227A: Swift-XRT refined Analysis
  2. GRB 200227A: Fermi GBM observation
  3. IceCube-200227A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  4. LIGO/Virgo S200219ac: Upper limits from Konus-Wind observations
  5. LIGO/Virgo S200213t: Upper limits from Konus-Wind observations
  6. LIGO/Virgo S200208q: Upper limits from Konus-Wind observations
  7. LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
  8. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  9. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  10. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  11. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  12. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  13. GRB 200219C: Swift-XRT afterglow confirmation
  14. GRB 200224A: Swift-XRT refined Analysis
  15. GRB 200219C: OAJ afterglow confirmation
  16. GRB 200219C: Swift-XRT afterglow detection
  17. GRB 200219C: Fermi GBM detection
  18. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  19. GRB 200219C: Fermi-LAT detection
  20. GRB 200219A, Swift-BAT refined analysis
  21. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  22. GRB 200219A: Swift-XRT refined Analysis correction
  23. GRB 200219A: Swift-XRT refined Analysis
  24. GRB 200219A: Fermi GBM observation
  25. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  26. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  27. GRB 200216B: Swift-XRT refined Analysis
  28. Further Swift-XRT observations of Swift J0840.7-3516
  29. GRB 200215A: Swift-XRT refined Analysis
  30. GRB 200215A: Fermi GBM detection
  31. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  32. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  33. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  34. ZTF20aajnksq: Upper limits from Konus-Wind observations
  35. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  36. GRB 200120A: Fermi GBM observation
  37. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  38. GRB 200205B: ESO/NTT near-infrared imaging
  39. GRB 200205B: Swift-XRT refined Analysis
  40. Swift GRB200205.81: Global MASTER-Net observations report
  41. Swift GRB200205.81: Global MASTER-Net OT detection
  42. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  43. LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
  44. GRB 200131A: Swift-XRT refined Analysis
  45. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  46. LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
  47. LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  48. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  49. GRB 200127A: Swift/UVOT Upper Limits
  50. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  51. GRB 200127A: Swift-XRT refined Analysis
  52. GRB 200125A: Swift-BAT refined analysis
  53. GRB 200125A: Further Swift-XRT observations
  54. GRB 200125B: Fermi GBM observations
  55. GRB 200125A: TNG detection of a NIR counterpart candidate
  56. Correction to GRB 200125A: Swift-XRT refined analysis
  57. GRB 200125A: Swift-XRT refined Analysis
  58. LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
  59. LIGO/Virgo S200115j: Further Swift-XRT sources
  60. GRB 200122A: Swift-XRT refined Analysis
  61. Fermi-LAT Gamma-ray Observations of IceCube-200120A
  62. LIGO/Virgo S200115j: Upper limits from Konus-Wind observations
  63. LIGO/Virgo S200114f: Upper limits from Konus-Wind observations
  64. LIGO/Virgo S200112r: Upper limits from Konus-Wind observations
  65. GRB 191031D: XMM-Newton upper limit
  66. IceCube-200120A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  67. LIGO/Virgo S200105ae: Upper limits from Konus-Wind observations
  68. LIGO/Virgo S191222n: Upper limits from Konus-Wind observations
  69. LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations
  70. LIGO/Virgo S191215w: Upper limits from Konus-Wind observations
  71. IceCube 200117A: No significant detection in HAWC
  72. LIGO/Virgo S191213g: Upper limits from Konus-Wind observations
  73. LIGO/Virgo S191205ah: Upper limits from Konus-Wind observations
  74. LIGO/Virgo S191204r: Upper limits from Konus-Wind observations
  75. LIGO/Virgo S191129u: Upper limits from Konus-Wind observations
  76. Fermi-LAT Gamma-ray Observations of IceCube-200117A
  77. LIGO/Virgo S200115j: LCO upper limits for ZTF20aafqvyc/AT2020yq from the McDonald Observatory 1-m telescope
  78. LIGO/Virgo S200115j: NIR upper limits for ZTF20aafqvyc/AT2020yq from the Palomar 200-inch telescope
  79. IceCube-200117A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  80. LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
  81. LIGO/Virgo S200115j: Swift-XRT sources
  82. LIGO/Virgo S200114f: Swift-XRT sources and observations
  83. LIGO/Virgo S200115j: No counterpart candidates in Fermi-LAT observations
  84. GRB 200115A: Nanshan-0.6m optical upper limit
  85. GRB 200115A: Swift detection of a burst
  86. LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations
  87. LIGO/Virgo S200114f: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  88. Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034
  89. LIGO/Virgo 200112r: No counterpart candidates in Fermi-LAT observations
  90. IceCube 200109A: No significant detection in HAWC
  91. Fermi-LAT ANTARES coincidence: No significant detection in HAWC
  92. GRB 200109A: Fermi GBM observation
  93. GRB 200107B: Swift-XRT refined Analysis
  94. Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  95. GRB 200109A: Swift-XRT refined Analysis
  96. GRB 200107B: Fermi GBM observation
  97. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  98. IceCube-200107A: No significant detection in HAWC
  99. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  100. LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations

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