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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 S250207bg: Updated NED Galaxies in the Localization Volume
  2. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  3. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  4. GRB 250205A: 1.3m DFOT optical upper limit
  5. LIGO/Virgo/KAGRA S250118az: Updated Sky localization
  6. LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
  7. GRB 250206A: EIRSAT-1 GMOD Detection
  8. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  9. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  10. GRB 250207B: Swift-XRT observations
  11. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  12. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  13. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  15. GRB 250207A: Swift-XRT refined Analysis
  16. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  17. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  18. GRB 250207A: Enhanced Swift-XRT position
  19. 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%
  20. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  21. GRB 250207A: REM IR afterglow detection
  22. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  23. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  24. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  25. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  26. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  27. GRB 250207A: REM optical afterglow detection
  28. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  29. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  30. GRB 250207A: Swift/UVOT Detection
  31. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  32. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  33. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  34. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  35. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  36. GRB 250129A: Continued AbAO and Mondy optical observations
  37. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  38. GRB 250207B: MAXI/GSC detection
  39. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  40. LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
  41. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  42. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  43. GRB 250207A: Swift detection of a burst with optical counterpart
  44. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  45. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  46. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  47. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  48. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  49. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  51. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  52. GRB 250205A: Fermi GBM Observation
  53. GRB 250205A: REM NIR upper limit
  54. GRB 250205A: Swift/UVOT Upper Limits
  55. LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
  56. EP250205a/GRB 250205A: Einstein Probe observation
  57. GRB 250127C: SVOM/GRM observation of a burst
  58. GRB 250204B: SVOM/GRM observation of a likely short burst
  59. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  60. GRB 250205A: Swift/XRT detection
  61. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  62. GRB250205A: SVOM/VT optical afterglow detection
  63. GRB 250205A: OHP/T193 optical counterpart candidate
  64. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  65. GRB 250205A: SVOM detection of a burst
  66. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  67. IPN triangulation of GRB 250201A
  68. LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
  69. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  70. GRB 250129A: Swift-BAT refined analysis
  71. EP 250108A: Upper limits from Fermi-GBM Observations
  72. IPN triangulation of GRB 250204B (short/hard)
  73. IPN triangulation of GRB 250202B
  74. LIGO/Virgo/KAGRA S250204ax: Updated Sky localization
  75. GRB 250204B: AstroSat CZTI detection of a short burst
  76. GRB 250129A: LCO late afterglow detection
  77. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  78. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  79. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  80. GRB 250202B: NuSTAR detection of the prompt emission
  81. GRB 250202B: Fermi GBM Detection
  82. GRB 250129a: Liverpool Telescope optical follow-up
  83. GRB 240129A: further SAO RAS optical observations
  84. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  85. LIGO/Virgo/KAGRA S250202cu: Updated Sky localization
  86. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  87. GRB 250129A: SVOM/C-GFT optical observations
  88. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  89. Swift GRB250129A: MASTER 4 days observations report
  90. GRB 250129A: 1.3m DFOT Optical observations
  91. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  92. GRB 250201A: Fermi GBM Final Real-time Localization
  93. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  94. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  95. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  96. GRB 250129A: SAO RAS optical observations
  97. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  98. GRB 250129A: COLIBRÍ Optical Observations
  99. GRB 250129A: iTelescope optical observation
  100. GRB 250129a: Liverpool Telescope optical follow-up

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