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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"

28131 results found.

  1. GRB 250206A: Fermi GBM Observation
  2. GRB 250205A / EP250205A: radio detection with the VLA
  3. EP250207b: Tentative z-band brightening source
  4. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  5. Konus-Wind detection of GRB 250206A
  6. GRB 250210A: SVOM/GRM observation of a long burst
  7. EP250207b: Liverpool Telescope possible optical counterpart
  8. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
  10. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  11. GRB 250207A: Skynet optical afterglow observations
  12. GRB 241128A: VIRT Optical Upper Limit
  13. EP250207b: Gemini GMOS-N z-band observations
  14. EP250207A: Upper limits from Fermi-GBM Observations
  15. EP250207b: a new X-ray transient detected by Einstein Probe
  16. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  17. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  18. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  19. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  20. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  21. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  22. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  23. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  24. GRB 250207A: 1.3m DFOT Optical observations
  25. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  26. GRB 250206A: Swift-XRT observations
  27. GRB 250129A: GRANDMA Continued Afterglow Detection
  28. GRB 250207A: Swift-BAT refined analysis
  29. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  30. LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
  31. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  32. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  33. GRB 250205A: 1.3m DFOT optical upper limit
  34. LIGO/Virgo/KAGRA S250118az: Updated Sky localization
  35. LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
  36. GRB 250206A: EIRSAT-1 GMOD Detection
  37. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  38. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  39. GRB 250207B: Swift-XRT observations
  40. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  41. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  42. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  44. GRB 250207A: Swift-XRT refined Analysis
  45. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  46. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  47. GRB 250207A: Enhanced Swift-XRT position
  48. CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
  49. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  50. GRB 250207A: REM IR afterglow detection
  51. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  52. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  53. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  54. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  55. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  56. GRB 250207A: REM optical afterglow detection
  57. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  58. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  59. GRB 250207A: Swift/UVOT Detection
  60. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  61. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  62. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  63. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  64. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  65. GRB 250129A: Continued AbAO and Mondy optical observations
  66. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  67. GRB 250207B: MAXI/GSC detection
  68. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  69. LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
  70. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  71. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  72. GRB 250207A: Swift detection of a burst with optical counterpart
  73. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  74. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  76. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  77. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  78. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  79. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  80. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  81. GRB 250205A: Fermi GBM Observation
  82. GRB 250205A: REM NIR upper limit
  83. GRB 250205A: Swift/UVOT Upper Limits
  84. LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
  85. EP250205a/GRB 250205A: Einstein Probe observation
  86. GRB 250127C: SVOM/GRM observation of a burst
  87. GRB 250204B: SVOM/GRM observation of a likely short burst
  88. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  89. GRB 250205A: Swift/XRT detection
  90. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  91. GRB250205A: SVOM/VT optical afterglow detection
  92. GRB 250205A: OHP/T193 optical counterpart candidate
  93. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  94. GRB 250205A: SVOM detection of a burst
  95. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  96. IPN triangulation of GRB 250201A
  97. LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
  98. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  99. GRB 250129A: Swift-BAT refined analysis
  100. EP 250108A: Upper limits from Fermi-GBM Observations

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