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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"
body:"GRB"
submitter:"Judith Racusin"

43956 results found.

  1. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  2. Fermi GRB 250215A: Global MASTER-Net observations report
  3. GRB 250215A: Fermi GBM Final Real-time Localization
  4. Fermi trigger No 761206993: Global MASTER-Net observations report
  5. GRB 250213A：SVOM/VT optical candidate
  6. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  7. EP250207b: Xinglong optical upper limit
  8. Fermi GRB 250214A: Global MASTER-Net observations report
  9. GRB 250213A: Swift ToO observations
  10. GRB 250214A: Fermi GBM Final Real-time Localization
  11. EP250212a: Xinglong optical upper limit
  12. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  13. GRB 250213A: SVOM detection of a burst
  14. EP250212a: Global MASTER-Net observations report
  15. GRB 250205A: VIRT Optical Upper Limit
  16. GRB 250205A: Leavitt Observatory optical upper limit
  17. GRB 250210A: GRBAlpha detection
  18. EP250207B: Chandra localization of the X-ray counterpart
  19. LIGO/Virgo/KAGRA S250206dm: FTW observations of counterpart candidates AT2025bbo and AT2025bcx, and of NED galaxies
  20. EP250207b: VLA radio upper limits
  21. EP250212a: Liverpool Telescope optical upper limits
  22. EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  23. GRB250101A: Radio upper limits from GMRT observations
  24. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  25. EP250207B: GTC z-band Observations
  26. Fermi GRB 250212A: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  28. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  29. Fermi trigger No 760945500: Global MASTER-Net observations report
  30. EP250207b: NOT optical counterpart candidate
  31. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  32. GRB 250211B: A long GRB detected by INTEGRAL
  33. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  34. GRB 250211A: Swift ToO observations
  35. Integral GRB250211.89: Global MASTER-Net observations report
  36. GRB 250212A: Fermi GBM Final Real-time Localization
  37. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  38. LIGO/Virgo/KAGRA S250211be: Updated Sky localization
  39. GRB 250207A: Fermi GBM Observation
  40. GRB 250206A: Fermi GBM Observation
  41. GRB 250205A / EP250205A: radio detection with the VLA
  42. IceCube-250207A: One candidate from the Zwicky Transient Facility
  43. EP250207b: Tentative z-band brightening source
  44. LIGO/Virgo/KAGRA S250206dm: continued in SOAR galaxy targeted observations and identification of one possible transient
  45. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  46. Konus-Wind detection of GRB 250207A
  47. Konus-Wind detection of GRB 250206A
  48. GRB 250210A: SVOM/GRM observation of a long burst
  49. EP250207b: Liverpool Telescope possible optical counterpart
  50. EP250207b: Global MASTER-Net observations report
  51. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  52. Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082)
  53. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  54. LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
  55. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  56. GRB 250207A: Skynet optical afterglow observations
  57. LIGO/VIRGO/KAGRA S250206dm: AT 2025bbo spectroscopic observations with NIRES on Keck II
  58. LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy
  59. GRB 241128A: VIRT Optical Upper Limit
  60. EP250207b: Gemini GMOS-N z-band observations
  61. EP250207A: Upper limits from Fermi-GBM Observations
  62. GRB 250210A: INTEGRAL SPI-ACS detection
  63. GRB 250210A: AstroSat CZTI detection
  64. EP250207b: a new X-ray transient detected by Einstein Probe
  65. LIGO/Virgo/KAGRA S250206dm: MASTER detection AT2025bbo
  66. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  67. Fermi GRB 250210A: Global MASTER-Net observations report
  68. GRB 250210A: Fermi GBM Final Real-time Localization
  69. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  70. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  71. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  72. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  73. IceCube Alert 250207.09: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  75. GRB 250204B: GRBAlpha detection
  76. GRB 250204A: GRBAlpha detection
  77. LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy
  78. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  79. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  80. GRB 250207A: 1.3m DFOT Optical observations
  81. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  82. GRB 250206A: Swift-XRT observations
  83. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  84. GRB 250129A: GRANDMA Continued Afterglow Detection
  85. GRB 250207A: Swift-BAT refined analysis
  86. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  87. LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
  88. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  89. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  90. GRB 250205A: 1.3m DFOT optical upper limit
  91. GRB 250206A: Tiled Swift observations
  92. LIGO/Virgo/KAGRA S250118az: Updated Sky localization
  93. LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
  94. GRB 250206A: EIRSAT-1 GMOD Detection
  95. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  96. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  97. GRB 250206A: Fermi-LAT detection
  98. GRB 250207B: Swift-XRT observations
  99. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  100. IceCube-250203A: No transient candidates from the Zwicky Transient Facility

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