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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"

4055 results found.

  1. LIGO/Virgo S200302c: Updated Sky Localization
  2. LIGO/Virgo S200302c: No significant counterpart candidates in Fermi-LAT observations
  3. LIGO/Virgo S200302c: No counterpart candidates in KAIT observations
  4. LIGO/Virgo S200302c: no counterpart candidates in the Swift/BAT observations
  5. LIGO/Virgo S200224ca: Transient found in Swift/UVOT counterpart search
  6. LIGO/Virgo S200302c: No counterpart candidates in HAWC observations
  7. LIGO/Virgo S200302c: Upper limits from Fermi-GBM Observations
  8. LIGO/Virgo S200302c: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  9. LIGO/Virgo S200302c : no neutrino counterpart candidate in ANTARES search
  10. LIGO/Virgo S200302c: upper limits from AGILE/MCAL observations
  11. LIGO/Virgo S200225q: AstroSat CZTI upper limits
  12. LIGO/Virgo S200219ac: AstroSat CZTI upper limits
  13. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  14. LIGO/Virgo S200302c: Upper limits from IceCube neutrino searches
  15. LIGO/Virgo S200302c: Identification of a GW compact binary merger candidate
  16. LIGO/Virgo S200302c: Global MASTER-Net observations report
  17. LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
  18. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
  19. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  20. IceCube-200227A : Upper limits from Insight-HXMT/HE observations
  21. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  22. LIGO/Virgo S200225q: Not observable by CALET
  23. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  24. LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
  25. LIGO/Virgo S200225q: Updated Sky Localization
  26. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  27. LIGO/Virgo S200219ac: Upper limits from Konus-Wind observations
  28. LIGO/Virgo S200213t: Upper limits from Konus-Wind observations
  29. LIGO/Virgo S200208q: Upper limits from Konus-Wind observations
  30. LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
  31. LIGO/Virgo S200225q: Upper limits from Insight-HXMT/HE observations
  32. LIGO/Virgo S200224ca: Upper limits from Insight-HXMT/HE observations
  33. LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
  34. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  35. LIGO/Virgo S200219ac: Updated Sky Localization
  36. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  37. LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
  38. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  39. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  40. LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
  41. LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
  42. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  43. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  44. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  45. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  46. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  47. LIGO/Virgo S200225q: Global MASTER-Net observations report
  48. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  49. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  50. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  51. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  52. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  53. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  54. LIGO/Virgo S200224ca: not observable by Fermi-GBM
  55. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  56. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  57. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  58. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  59. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  60. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  61. GRB 200224A: Swift-XRT refined Analysis
  62. GRB 200224C: Fermi GBM Final Real-time Localization
  63. GRB 200224A: Tautenburg observations
  64. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  65. Fermi trigger No 604213554: Global MASTER-Net observations report
  66. GRB 200224B: Fermi GBM Final Real-time Localization
  67. GRB 200224A: Swift detection of a burst
  68. Swift GRB200224.14: Global MASTER-Net observations report
  69. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  70. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  71. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  72. IPN triangulation of GRB 200219B (inconsistent with the LIGO/Virgo S200219ac)
  73. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  74. LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
  75. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  76. LIGO/Virgo S200219ac: No transient candidates in CALET observations
  77. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  78. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  79. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  80. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  81. LIGO/Virgo S200213t: Keck/LRIS spectroscopy of counterpart candidates from the Zwicky Transient Facility
  82. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  83. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  84. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  85. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  86. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  87. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  88. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  89. LIGO/Virgo S200219ac: Global MASTER-Net observations report
  90. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  91. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  92. LIGO/Virgo S200213t: APO Upper Limits for ZTF20aanakes/AT2020cly
  93. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  94. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  95. LIGO/Virgo S200213t: Updated Sky Localization
  96. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  97. LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
  98. LIGO/Virgo S200213t: Possible host galaxies in the bilby skymap
  99. LIGO/Virgo S200213t: Updated Sky Localization
  100. LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3

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