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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  2. LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
  3. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  4. LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
  5. LIGO/Virgo S200225q: Global MASTER-Net observations report
  6. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  7. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  8. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  9. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  10. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  11. GRB 200224A: Swift-BAT refined analysis
  12. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  13. LIGO/Virgo S200224ca: not observable by Fermi-GBM
  14. GRB 200224A: LCO Upper Limits
  15. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  16. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  17. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  18. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  19. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  20. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  21. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  22. IPN triangulation of GRB 200224C
  23. GRB 200224A: Swift/UVOT Detection
  24. Correction in name: GRB 200224B and GRB 200224C (not GRB 200224A)
  25. GRB 200219C: Swift-XRT afterglow confirmation
  26. GRB 200224A: Swift-XRT refined Analysis
  27. GRB 200224C: Fermi GBM Final Real-time Localization
  28. GRB 200224A: Tautenburg observations
  29. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  30. Fermi trigger No 604213554: Global MASTER-Net observations report
  31. GRB 200224B: Fermi GBM Final Real-time Localization
  32. GRB 200224A: Swift detection of a burst
  33. Swift GRB200224.14: Global MASTER-Net observations report
  34. GRB 200223A: Fermi GBM Final Real-time Localization
  35. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  36. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  37. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  38. IPN triangulation of GRB 200219B (inconsistent with the LIGO/Virgo S200219ac)
  39. GRB 200219C: OAJ afterglow confirmation
  40. GRB 200219A: UVOT Upper Limits
  41. GRB 200219A: FRAM-Auger optical limit
  42. GRB 200219C: CALET Gamma-Ray Burst Monitor detection
  43. GRB 200219С: Mondy and TSHAO optical observations
  44. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  45. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  46. GRB 200221A: Fermi GBM Final Real-time Localization
  47. Fermi trigger No 603949983: Global MASTER-Net observations report
  48. GRB 200219C: Swift-XRT afterglow detection
  49. GRB 200219C: DDOTI Observations
  50. GRB 200219C: Fermi GBM detection
  51. LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
  52. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  53. GRB 200219C: Tiled Swift observations
  54. GRB 200219C: Fermi-LAT detection
  55. GRB 200215A: LCO Optical Upper Limits
  56. LIGO/Virgo S200219ac: No transient candidates in CALET observations
  57. GRB 200219A, Swift-BAT refined analysis
  58. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  59. Fermi trigger No 603849435: Global MASTER-Net observations report
  60. GRB 200219C: Fermi GBM Final Real-time Localization
  61. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  62. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  63. GRB 200219A: Swift-XRT refined Analysis correction
  64. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  65. LIGO/Virgo S200213t: Keck/LRIS spectroscopy of counterpart candidates from the Zwicky Transient Facility
  66. GRB 200219A: Swift-XRT refined Analysis
  67. GRB 200219A: Enhanced Swift-XRT position
  68. GRB 200219A: Fermi GBM observation
  69. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  70. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  71. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  72. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  73. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  74. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  75. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo S200219ac: Global MASTER-Net observations report
  77. GRB 200216B: second epoch optical upper limit at Mondy observatory
  78. GRB 200219B: Fermi GBM Final Real-time Localization
  79. GRB 200219A: MASTER catalog automatic possible Host Galaxy candidate
  80. GRB 200219A: Swift detection of a short burst
  81. Swift GRB200219.32: Global MASTER-Net observations report
  82. GRB 200219A: Fermi GBM Final Real-time Localization
  83. GRB 200216B: Mondy and AbAO optical upper limits
  84. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  85. GRB 200216B: Swift-XRT refined Analysis
  86. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  87. LIGO/Virgo S200213t: APO Upper Limits for ZTF20aanakes/AT2020cly
  88. GRB 200216B: Swift-BAT refined analysis
  89. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  90. Further Swift-XRT observations of Swift J0840.7-3516
  91. GRB 200216B - possible IR counterpart from VLT
  92. GRB 200215A: CALET Gamma-Ray Burst Monitor detection
  93. GRB 200216A: Fermi GBM detection
  94. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  95. GRB 200216B: z-band limit from NOT
  96. GRB 200216B: Fermi GBM observation
  97. GRB 200216B: Swift/UVOT Upper Limits
  98. GRB 200216A: Swift/BAT detection and arcminute localization from GUANO
  99. GRB 200216B: Enhanced Swift-XRT position
  100. GRB 200215A: RATIR Optical Observations

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