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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').
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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"
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submitter:"Judith Racusin"

28251 results found.

  1. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  2. IceCube 250406.951: DDOTI Optical Observations
  3. GRB 250406A: AstroSat CZTI detection
  4. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  5. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  6. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  7. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  8. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  9. Konus-Wind detection of GRB 250404A / EP250404a
  10. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  11. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  12. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  13. EP250402a: Optical upper limit with PD 1.3m observations
  14. GRB 250404A / EP250404a: NOT optical observations
  15. GRB 250331D: Swift-XRT afterglow detection
  16. GRB 250404B: AstroSat CZTI detection of a short burst
  17. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  18. EP250404a: REM optical/NIR observations
  19. EP250404a: Seimei/TriCCS optical counterpart detection
  20. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  21. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  22. EP250404a: LCO optical counterpart detection
  23. EP250404a: Xinglong decaying optical counterpart
  24. GRB 250403A: Montarrenti Observatory optical detection
  25. GRB 250404A: Fermi GBM Detection
  26. GRB 250403A: KAIT optical observations
  27. EP250404a: AKO Optical Afterglow Detection
  28. EP250404a: LAST detection of optical counterpart
  29. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  30. GRB 250403A: Fermi GBM observations
  31. GRB 250327B: VIRT Optical Upper Limit
  32. EP250404a: Mephisto multi-band optical detection
  33. GRB 250331C Swift-BAT refined analysis
  34. GRB 250331B Swift-BAT refined analysis
  35. GRB 250330A Swift-BAT refined analysis
  36. EP250321A: J band upper limit by SYSU 80cm telescope
  37. EP250404a: Nanshan/HMT optical counterpart detection
  38. EP250404a: Einstein Probe detection of an X-ray transient
  39. GRB 250403A: Swift/UVOT Detection
  40. GRB 250402A: Swift/UVOT Upper Limits
  41. EP250402a: Optical upper limit with Kinder observations
  42. GRB 250403A: REM NIR afterglow detection
  43. GRB 250403A: LCO optical counterpart detection
  44. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  45. GRB 250403A: JinShan optical observations
  46. GRB 250403A: Optical counterpart detection by LCO.
  47. EP250402a: EP-FXT follow-up observations
  48. GRB 250403A: Swift-XRT observations
  49. GRB 250322A: 10 GHz VLA radio upper limits
  50. GRB 250403A: GMG Optical Observation
  51. GRB 250403A: 1.6m Mephisto multi-band optical detection
  52. GRB 250402A: Fermi GBM Observation
  53. GRB 250403A: SVOM/C-GFT optical observations
  54. GRB 250402A: Swift-XRT observations
  55. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  56. GRB 250402A: REM optical/NIR upper limits
  57. GRB 250402A: LCO optical counterpart detection
  58. EP250402a: Einstein Probe detection of a fast X-ray transient
  59. GRB 250402B: AstroSat CZTI detection of a short burst
  60. GRB 250402A: SVOM/VT optical counterpart
  61. GRB 250402A: SVOM detection of a burst
  62. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  63. GRB 250329B: Swift/UVOT Upper Limit
  64. GRB 250329A: Swift/UVOT Upper Limit
  65. GRB 250327B: Swift/UVOT Detection
  66. GRB 250327A: Swift/UVOT Upper Limits
  67. GRB 250331E: SVOM/GRM observation
  68. GRB 250327B: Kilonova-Catcher Observations
  69. GRB250331D: AbAO optical observations
  70. GRB 250331D: Fermi GBM observation
  71. GRB 250331C: Swift/UVOT Upper Limits
  72. GRB 250331B: Swift/UVOT Upper Limits
  73. GRB 250328A: AbAO AS-32 Optical Observations
  74. GRB 250219A: NOT candidate host galaxy detection
  75. GRB 250331D: Swift-XRT observations
  76. GRB 250331C: Swift-XRT refined Analysis
  77. GRB 250331B: Swift-XRT refined Analysis
  78. GRB 250331B: Swift-XRT refined Analysis
  79. GRB 250322B possible detection by the AstroSat Satellite
  80. GRB 250330B: SVOM/GRM observation of a short burst
  81. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  82. GRB 250330B: EIRSAT-1 GMOD Detection
  83. GRB 250327A Swift-BAT refined analysis
  84. LIGO/Virgo/KAGRA S250331o: Updated Sky localization
  85. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  86. Swift GRB 250331C: Global MASTER-Net observations report
  87. Swift GRB 250331B: Global MASTER-Net observations report
  88. GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew
  89. GRB 250331C: Enhanced Swift-XRT position
  90. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  91. LIGO/Virgo/KAGRA S250331o: NED Galaxies in the 3-Initial Localization Volume
  92. GRB 250331B: Enhanced Swift-XRT position
  93. GRB 250320C : SVOM detection of a burst through offline search
  94. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  95. GRB 250330A: VLT/FORS2 Afterglow Detection
  96. GRB20250327B: 45th Parallel Observatory upper limit
  97. GRB 250328A: Swift/UVOT Detection
  98. GRB 250328A: Swift-XRT refined Analysis
  99. Fermi-LAT gamma-ray observations of IceCube-250330A
  100. SVOM/sb25033102 is a false trigger

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