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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"

22215 results found.

  1. GRB 250309B: PRIME near-infrared detection
  2. EP250304a: Chandra detection
  3. GRB 250311A/EP250311a: TRT optical upper limit
  4. IceCube-250309A: MITSuME Akeno and Seimei/TriCCS optical observations
  5. GRB 250311A: Tiled Swift observations
  6. EP250311a/GRB 250311A: EP-WXT detection
  7. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  8. GRB 250309B / AT2025dws: further SAO RAS optical observations
  9. IceCube-250309A: Upper limits from Fermi-GBM Observations
  10. GRB 250309B / AT2025dws: KMTNet-CTIO optical observations
  11. IceCube-241224A: MASTER detection of PKS 1217+02 blazar flare with Zhirkov effect
  12. GRB 250309B/AT2025dws : COLIBRÍ Detection of the Optical Counterpart
  13. GRB 250309B / IceCube-250309A: GECAM-B observations
  14. Liverpool Telecope observations of AT 2025dws / GRB 250309B
  15. GRB 250309B / AT2025dws: SAO RAS optical observations
  16. GRB 250309B / AT2025dws: Swift-UVOT detection
  17. AT 2025dws, likely optical counterpart of GRB 250309B: LCO confirmation of fast fading
  18. Fermi GRB 250309B: Global MASTER-Net observations report
  19. Fermi GRB 250309A: Global MASTER-Net observations report
  20. GRB250309B: One candidate counterpart from the Zwicky Transient Facility
  21. IceCube-250309A: No candidates from the Zwicky Transient Facility
  22. Fermi-LAT gamma-ray observations of IceCube-250309A
  23. GRB 250308A: SVOM/GRM detection of QPO in the tail emission
  24. GRB 230509B: Tiled Swift observations
  25. IceCube-250309A - IceCube observation of a high-energy neutrino candidate track-like event
  26. IceCube Alert 250309.32: Global MASTER-Net observations report
  27. EP250308a: Global MASTER-Net observations report
  28. EP250308a: GSP optical upper limit
  29. EP250308a: FTW optical and NIR upper limits
  30. EP250308a: Einstein Probe detection of an X-ray transient
  31. Fermi GRB 250307A: Global MASTER-Net observations report
  32. Konus-Wind detection of GRB 250306A
  33. EP250304a: MeerKAT detection of a possible radio counterpart
  34. EP250302a:Xinglong optical observations
  35. Fermi trigger No 762963055: Global MASTER-Net observations report
  36. Swift GRB 250306A: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S250207bg: Update-5 NED Galaxies in the Localization Volume
  38. GRB250101A: Radio upper limits from VLA observations
  39. EP250304A: Upper limits from Fermi-GBM Observations
  40. Fermi GRB 250305A: Global MASTER-Net observations report
  41. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  42. EP250302a: Optical Observations at CrAO and SAO RAS
  43. EP 250304A: Optical counterpart detection by LCO
  44. EP250302A: 1.3m DFOT optical afterglow detection
  45. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  46. Konus-Wind detection of GRB 250222A
  47. EP250304a: REM NIR upper limits
  48. EP250302a: Mondy Continued Optical Observations
  49. EP250304a: TRT optical counterpart detection
  50. EP250304a: Global MASTER-Net observations report
  51. EP250302a: SVOM/VT optical observation
  52. EP250302a: SAO RAS optical observations
  53. EP250225a: the candidate optical counterpart is an AGN
  54. EP250302a: Kinder optical follow-up observations
  55. EP250302a: NUTTelA-TAO Early Measurments
  56. EP250302a: REM NIR upper limits
  57. IceCube-241113A: MASTER flaring blazar 5BZB J1311+0853 with Zhirkov effect
  58. EP250302a: Mondy Observations and Optical Light Curve
  59. EP250302a: VLT/MUSE optical redshift z = 1.131
  60. EP250302A: VLT near-infrared observations
  61. EP250302A: VLT/X-shooter tentative redshift
  62. EP250302a: OHP/T193 optical and spectroscopic observations
  63. EP250302a: Global MASTER-Net observations report
  64. EP250302a: Xinglong F60B optical observation
  65. EP250302a: Swift-XRT observations of a fading X-ray source
  66. EP250302a: Einstein Probe detection of an X-ray transient
  67. EP250302a: SVOM/C-GFT optical observations
  68. GRB 250226A: GRANDMA Optical Observations
  69. EP250302a: Montarrenti Observatory optical detection
  70. Fermi GRB 250302A: Global MASTER-Net observations report
  71. EP250302a: FTW optical and NIR detection
  72. EP250302a: Nanshan/HMT optical counterpart detection
  73. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  74. GRB 250225B: VLT near-infrared afterglow confirmation
  75. EP250228a: Optical observations with Kinder and Swift/UVOT
  76. Konus-Wind detection of GRB 250226A
  77. GRB 250226A: KAO Optical Upper Limit
  78. GRB 250226A: AbAO AS-32 Optical Upper Limit
  79. EP250227a: Global MASTER-Net observations report
  80. EP250223A: Upper limits from Fermi-GBM Observations
  81. EP250227a: TRT optical upper limit
  82. GRB 250225B: VLT/HAWKI near-infrared observations
  83. EP250227a: Optical upper limits with Kinder observations
  84. EP250227a: NOT optical observations
  85. EP250228a: updates on the EP observations
  86. GRB 250226A: Fermi GBM Observation
  87. EP250223a: J band upper limit by SYSU 80cm telescope
  88. EP250228a: Global MASTER-Net observations report
  89. GRB 250226A / EP250226a: LCO detection of the afterglow
  90. GRB 250225B: VLT/Xshooter imaging
  91. GRB 250205A / EP250205A: further radio observations with the VLA
  92. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  93. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  94. GRB 250225B: INTEGRAL SPI-ACS detection
  95. EP250225a: NOT optical candidate counterpart
  96. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  97. EP250226a / GRB 250226A: SVOM/VT optical observations
  98. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  99. EP250225a: TRT optical upper limits
  100. EP250226a/GRB 250226A: 1.6m Mephisto observations

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