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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

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24603 results found.

  1. LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
  2. GRB 250206A: EIRSAT-1 GMOD Detection
  3. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  4. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  5. GRB 250207B: Swift-XRT observations
  6. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  7. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  8. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  10. GRB 250207A: Swift-XRT refined Analysis
  11. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  12. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  13. GRB 250207A: Enhanced Swift-XRT position
  14. 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%
  15. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  16. GRB 250207A: REM IR afterglow detection
  17. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  18. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  19. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  20. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  21. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  22. GRB 250207A: REM optical afterglow detection
  23. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  25. GRB 250207A: Swift/UVOT Detection
  26. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  27. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  28. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  29. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  30. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  31. GRB 250129A: Continued AbAO and Mondy optical observations
  32. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  33. GRB 250207B: MAXI/GSC detection
  34. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  35. LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
  36. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  37. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  38. GRB 250207A: Swift detection of a burst with optical counterpart
  39. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  40. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  41. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  42. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  43. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  44. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  45. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  46. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  47. GRB 250205A: Fermi GBM Observation
  48. GRB 250205A: REM NIR upper limit
  49. GRB 250205A: Swift/UVOT Upper Limits
  50. LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
  51. EP250205a/GRB 250205A: Einstein Probe observation
  52. GRB 250127C: SVOM/GRM observation of a burst
  53. GRB 250204B: SVOM/GRM observation of a likely short burst
  54. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  55. GRB 250205A: Swift/XRT detection
  56. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  57. GRB250205A: SVOM/VT optical afterglow detection
  58. GRB 250205A: OHP/T193 optical counterpart candidate
  59. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  60. GRB 250205A: SVOM detection of a burst
  61. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  62. IPN triangulation of GRB 250201A
  63. LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
  64. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  65. GRB 250129A: Swift-BAT refined analysis
  66. EP 250108A: Upper limits from Fermi-GBM Observations
  67. IPN triangulation of GRB 250204B (short/hard)
  68. IPN triangulation of GRB 250202B
  69. LIGO/Virgo/KAGRA S250204ax: Updated Sky localization
  70. GRB 250204B: AstroSat CZTI detection of a short burst
  71. GRB 250129A: LCO late afterglow detection
  72. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  73. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  74. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  75. GRB 250202B: NuSTAR detection of the prompt emission
  76. GRB 250202B: Fermi GBM Detection
  77. GRB 250129a: Liverpool Telescope optical follow-up
  78. GRB 240129A: further SAO RAS optical observations
  79. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  80. LIGO/Virgo/KAGRA S250202cu: Updated Sky localization
  81. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  82. GRB 250129A: SVOM/C-GFT optical observations
  83. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  84. Swift GRB250129A: MASTER 4 days observations report
  85. GRB 250129A: 1.3m DFOT Optical observations
  86. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  87. GRB 250201A: Fermi GBM Final Real-time Localization
  88. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  89. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  90. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  91. GRB 250129A: SAO RAS optical observations
  92. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  93. GRB 250129A: COLIBRÍ Optical Observations
  94. GRB 250129A: iTelescope optical observation
  95. GRB 250129a: Liverpool Telescope optical follow-up
  96. GRB 250129A: TNG NIR afterglow detection
  97. GRB 250129A: AKO Optical Afterglow Detection
  98. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  99. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  100. GRB 250128B: VLA radio upper limit

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