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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

7450 results found.

  1. LIGO/Virgo S200219ac: AstroSat CZTI upper limits
  2. LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
  3. LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
  4. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  5. GRB 200228B: KAIT Optical Upper Limit
  6. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
  7. IceCube-200227A : Upper limits from Insight-HXMT/HE observations
  8. HAWC-200216A: No Neutrino Counterpart in ANTARES Search
  9. IceCube-200227A: Upper limits from Fermi-GBM Observations
  10. IceCube-200227A: IceCube observation of a high-energy neutrino candidate event
  11. GRB 200227A: Swift detection of a burst
  12. LIGO/Virgo S200225q: Not observable by CALET
  13. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  14. LIGO/Virgo S200225q: Updated Sky Localization
  15. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  16. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  17. LIGO/Virgo S200219ac: Updated Sky Localization
  18. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  19. LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
  20. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  21. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  22. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  23. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  24. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  25. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  26. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  27. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  28. GRB 200219C: Swift-XRT afterglow confirmation
  29. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  30. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  31. GRB 200219C: Mondy and TSHAO optical observations
  32. GRB 200219C: DDOTI Observations
  33. GRB 200219C: Tiled Swift observations
  34. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  35. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  36. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  37. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  38. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  39. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  40. GRB 200219A: MASTER catalog automatic possible Host Galaxy candidate
  41. GRB 200219A: Swift detection of a short burst
  42. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  43. GRB 200216B - possible IR counterpart from VLT
  44. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  45. GRB 200216B: Swift detection of a burst
  46. LIGO/Virgo S200213t: Updated Sky Localization
  47. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  48. LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
  49. LIGO/Virgo S200213t: Updated Sky Localization
  50. LIGO/Virgo S200213t: Lulin Follow-Up Observations
  51. GRB 200215A: Swift detection of a burst
  52. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  53. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  54. LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
  55. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  56. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  57. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  58. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  59. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  60. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  61. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  62. LIGO/Virgo S200213t: Neutrino and galaxies cross-match
  63. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  64. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  65. LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo S200208q: Updated Sky Localization
  67. LIGO/Virgo S200208q: Not observable by CALET
  68. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  69. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  70. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  71. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  72. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  73. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  74. Swift Trigger 954840 is not a GRB
  75. GRB 200205B: Swift detection of a burst with optical counterpart
  76. AMON IceCube-HAWC_200202A : No neutrino counterpart seen with ANTARES
  77. GRB 200131A: Swift detection of a burst with an optical counterpart
  78. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  79. LIGO/Virgo S200129m: Upper limits from CALET observations.
  80. LIGO/Virgo S200129m: NED Galaxies in the 50% Localization Volume
  81. LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
  82. LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
  83. LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
  84. LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
  86. LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
  87. LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
  88. LIGO/Virgo S200128d: Identification of a GW compact binary merger candidate
  89. LIGO/Virgo S200128d: Upper limits from IceCube neutrino searches
  90. GRB 200127A: Swift detection of a burst
  91. GRB 200125A: AbAO optical upper limit
  92. GRB 200125A: TNG detection of a NIR counterpart candidate
  93. GRB 200115A: Assy optical observations
  94. LIGO/Virgo S191222n: AstroSat CZTI upper limits
  95. LIGO/Virgo S200112r: AstroSat CZTI upper limits
  96. LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
  97. IPN Triangulation of GRB 200120A
  98. GRB 200122A: GOTO non-detection of optical afterglow
  99. GRB 200122A: Swift detection of a burst
  100. IceCube-200120A: not observable by Fermi-GBM

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