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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').
Advanced Search

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"
body:"GRB"
submitter:"Judith Racusin"

20521 results found.

  1. GRB 241128A: VIRT Optical Upper Limit
  2. EP250207b: Gemini GMOS-N z-band observations
  3. EP250207b: a new X-ray transient detected by Einstein Probe
  4. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  5. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  6. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  7. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  8. GRB 250207A: 1.3m DFOT Optical observations
  9. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  10. GRB 250206A: Swift-XRT observations
  11. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  12. GRB 250129A: GRANDMA Continued Afterglow Detection
  13. LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
  14. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  15. GRB 250205A: 1.3m DFOT optical upper limit
  16. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  17. GRB 250207B: Swift-XRT observations
  18. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  19. EP250207a: EP-WXT detection and XRT follow-up observation
  20. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  21. GRB 250207A: Swift-XRT refined Analysis
  22. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  23. GRB 250207A: Enhanced Swift-XRT position
  24. 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%
  25. LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
  26. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  27. GRB 250207A: REM IR afterglow detection
  28. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  29. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  30. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  31. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  32. GRB 250207A: REM optical afterglow detection
  33. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  35. GRB 250207A: Swift/UVOT Detection
  36. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  37. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  38. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  39. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  40. GRB 250129A: Continued AbAO and Mondy optical observations
  41. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  42. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  43. GRB 250207A: Swift detection of a burst with optical counterpart
  44. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  45. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  46. GRB 250205A: REM NIR upper limit
  47. GRB 250205A: Swift/UVOT Upper Limits
  48. EP250205a/GRB 250205A: Einstein Probe observation
  49. GRB 250127C: SVOM/GRM observation of a burst
  50. GRB 250204B: SVOM/GRM observation of a likely short burst
  51. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  52. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  53. GRB250205A: SVOM/VT optical afterglow detection
  54. GRB 250205A: OHP/T193 optical counterpart candidate
  55. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  56. GRB 250205A: SVOM detection of a burst
  57. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  58. IPN triangulation of GRB 250201A
  59. Konus-Wind detection of GRB 250202B
  60. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  61. IPN triangulation of GRB 250202B
  62. GRB 250129A: LCO late afterglow detection
  63. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  64. GRB 250204A: Fermi GBM Final Real-time Localization
  65. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  66. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  67. GRB 250129a: Liverpool Telescope optical follow-up
  68. GRB 240129A: further SAO RAS optical observations
  69. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  70. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  71. GRB 250129A: SVOM/C-GFT optical observations
  72. Swift GRB250129A: MASTER 4 days observations report
  73. GRB 250129A: 1.3m DFOT Optical observations
  74. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  75. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  76. GRB 250129A: SAO RAS optical observations
  77. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  78. GRB 250129A: COLIBRÍ Optical Observations
  79. GRB 250129A: iTelescope optical observation
  80. GRB 250129a: Liverpool Telescope optical follow-up
  81. GRB 250129A: TNG NIR afterglow detection
  82. GRB 250129A: AKO Optical Afterglow Detection
  83. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  84. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  85. GRB 250128B: VLA radio upper limit
  86. Ep250125A: 1.3m DFOT optical upper limit
  87. GRB 250129A: Skynet optical observations
  88. GRB 250128B: TNG optical upper limit
  89. GRB 250129A: Swift/UVOT Detection
  90. GRB 250128B: VLT/HAWKI near-infrared observations
  91. GRB 250127A: CrAO and Terskol optical upper limits
  92. GRB 250129A: Enhanced Swift-XRT position
  93. GRB 250128B: NOT optical upper limit
  94. GRB 250128B: VLT/FORS2 optical observations
  95. GRB 250129A: REM optical/NIR afterglow detection
  96. GRB 250129A: OHP/T193 optical and spectroscopy observations
  97. GRB 250129A: Early afterglow detection by LCO.
  98. GRB 250128B: OHP/T193 optical upper limit
  99. GRB 250129A: LCO optical observations
  100. GRB 250129A: NOT optical observations and redshift confirmation

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