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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"

28232 results found.

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

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