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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.

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

28084 results found.

  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 S200224ca: No counterpart candidates in Fermi-LAT observations
  6. LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  7. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  9. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  10. GRB 200224A: Swift-BAT refined analysis
  11. LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  12. GRB 200224A: LCO Upper Limits
  13. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  14. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  15. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  16. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  17. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  18. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
  19. GRB 200224A: Swift/UVOT Detection
  20. GRB 200224A: Swift-XRT refined Analysis
  21. GRB 200224A: Tautenburg observations
  22. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  23. GRB 200224A: Swift detection of a burst
  24. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  25. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  26. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  27. GRB 200219C: OAJ afterglow confirmation
  28. GRB 200219A: UVOT Upper Limits
  29. GRB 200219C: Mondy and TSHAO optical observations
  30. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  31. GRB 200219C: Swift-XRT afterglow detection
  32. GRB 200219C: DDOTI Observations
  33. GRB 200219C: Fermi GBM detection
  34. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  35. GRB 200215A: LCO Optical Upper Limits
  36. GRB 200219A, Swift-BAT refined analysis
  37. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  38. Fermi trigger No 603849435: Global MASTER-Net observations report
  39. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  40. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  41. GRB 200219A: Swift-XRT refined Analysis correction
  42. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  43. GRB 200219A: Enhanced Swift-XRT position
  44. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  45. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  46. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  47. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  48. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  49. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  50. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  51. GRB 200216B: second epoch optical upper limit at Mondy observatory
  52. GRB 200219A: MASTER catalog automatic possible Host Galaxy candidate
  53. GRB 200219A: Swift detection of a short burst
  54. GRB 200216B: Mondy and AbAO optical upper limits
  55. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  56. GRB 200216B: Swift-XRT refined Analysis
  57. GRB 200216B: Swift-BAT refined analysis
  58. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  59. Further Swift-XRT observations of Swift J0840.7-3516
  60. GRB 200216A: Fermi GBM detection
  61. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  62. GRB 200216B: z-band limit from NOT
  63. GRB 200216B: Fermi GBM observation
  64. GRB 200216B: Swift/UVOT Upper Limits
  65. GRB 200216B: Enhanced Swift-XRT position
  66. GRB 200215A: RATIR Optical Observations
  67. GRB 200216B: Nanshan/NEXT early optical upper limit and possible host galaxy
  68. GRB 200216B: GMG upper limit
  69. GRB 200216B: Swift detection of a burst
  70. GRB 200215A: UKIRT H-band observations
  71. GRB 200215A: Swift-BAT refined analysis
  72. LIGO/Virgo S200213t: Updated Sky Localization
  73. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  74. LIGO/Virgo S200213t: Updated Sky Localization
  75. GRB 200215A: Swift-XRT refined Analysis
  76. GRB 200215A: Swift/UVOT Upper Limits
  77. GRB 200215A: Enhanced Swift-XRT position
  78. GRB 200215A: Optical observations form Calar Alto 2.2m
  79. GRB 200215A: Fermi GBM detection
  80. GRB 200215A: Liverpool Telescope upper limits
  81. LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3
  82. GRB 200215A Possible host galaxy in PanSTARRS
  83. GRB 200215A: Nanshan/NEXT optical upper limit
  84. GRB 200215A: Swift detection of a burst
  85. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  86. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  87. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  88. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  89. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  90. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  91. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  92. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  93. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  94. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  95. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  96. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  97. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  98. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  99. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  100. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation

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