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

46006 results found.

  1. Fermi GRB 250215A: Global MASTER-Net observations report
  2. GRB 250215A: Fermi GBM Final Real-time Localization
  3. Fermi trigger No 761206993: Global MASTER-Net observations report
  4. GRB 250213A：SVOM/VT optical candidate
  5. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  6. EP250207b: Xinglong optical upper limit
  7. Fermi GRB 250214A: Global MASTER-Net observations report
  8. GRB 250213A: Swift ToO observations
  9. GRB 250214A: Fermi GBM Final Real-time Localization
  10. EP250212a: Xinglong optical upper limit
  11. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  12. GRB 250213A: SVOM detection of a burst
  13. EP250212a: Global MASTER-Net observations report
  14. GRB 250205A: VIRT Optical Upper Limit
  15. GRB 250205A: Leavitt Observatory optical upper limit
  16. GRB 250210A: GRBAlpha detection
  17. EP250207B: Chandra localization of the X-ray counterpart
  18. LIGO/Virgo/KAGRA S250206dm: FTW observations of counterpart candidates AT2025bbo and AT2025bcx, and of NED galaxies
  19. EP250207b: VLA radio upper limits
  20. EP250212a: Liverpool Telescope optical upper limits
  21. EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  22. GRB250101A: Radio upper limits from GMRT observations
  23. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  24. EP250207B: GTC z-band Observations
  25. Fermi GRB 250212A: Global MASTER-Net observations report
  26. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  27. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  28. Fermi trigger No 760945500: Global MASTER-Net observations report
  29. EP250207b: NOT optical counterpart candidate
  30. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  31. GRB 250211B: A long GRB detected by INTEGRAL
  32. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  33. GRB 250211A: Swift ToO observations
  34. Integral GRB250211.89: Global MASTER-Net observations report
  35. GRB 250212A: Fermi GBM Final Real-time Localization
  36. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  37. LIGO/Virgo/KAGRA S250211be: Updated Sky localization
  38. GRB 250207A: Fermi GBM Observation
  39. GRB 250206A: Fermi GBM Observation
  40. GRB 250205A / EP250205A: radio detection with the VLA
  41. IceCube-250207A: One candidate from the Zwicky Transient Facility
  42. EP250207b: Tentative z-band brightening source
  43. LIGO/Virgo/KAGRA S250206dm: continued in SOAR galaxy targeted observations and identification of one possible transient
  44. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  45. Konus-Wind detection of GRB 250207A
  46. Konus-Wind detection of GRB 250206A
  47. GRB 250210A: SVOM/GRM observation of a long burst
  48. EP250207b: Liverpool Telescope possible optical counterpart
  49. EP250207b: Global MASTER-Net observations report
  50. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  51. Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082)
  52. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  53. LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
  54. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  55. GRB 250207A: Skynet optical afterglow observations
  56. LIGO/VIRGO/KAGRA S250206dm: AT 2025bbo spectroscopic observations with NIRES on Keck II
  57. LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy
  58. GRB 241128A: VIRT Optical Upper Limit
  59. EP250207b: Gemini GMOS-N z-band observations
  60. EP250207A: Upper limits from Fermi-GBM Observations
  61. GRB 250210A: INTEGRAL SPI-ACS detection
  62. GRB 250210A: AstroSat CZTI detection
  63. EP250207b: a new X-ray transient detected by Einstein Probe
  64. LIGO/Virgo/KAGRA S250206dm: MASTER detection AT2025bbo
  65. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  66. Fermi GRB 250210A: Global MASTER-Net observations report
  67. GRB 250210A: Fermi GBM Final Real-time Localization
  68. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  69. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  70. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  71. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  72. IceCube Alert 250207.09: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  74. GRB 250204B: GRBAlpha detection
  75. GRB 250204A: GRBAlpha detection
  76. LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy
  77. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  78. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  79. GRB 250207A: 1.3m DFOT Optical observations
  80. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  81. GRB 250206A: Swift-XRT observations
  82. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  83. GRB 250129A: GRANDMA Continued Afterglow Detection
  84. GRB 250207A: Swift-BAT refined analysis
  85. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  86. LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
  87. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  88. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  89. GRB 250205A: 1.3m DFOT optical upper limit
  90. GRB 250206A: Tiled Swift observations
  91. LIGO/Virgo/KAGRA S250118az: Updated Sky localization
  92. LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
  93. GRB 250206A: EIRSAT-1 GMOD Detection
  94. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  95. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  96. GRB 250206A: Fermi-LAT detection
  97. GRB 250207B: Swift-XRT observations
  98. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  99. IceCube-250203A: No transient candidates from the Zwicky Transient Facility
  100. LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS

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