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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"

7449 results found.

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

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