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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"

26731 results found.

  1. EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  2. GRB250101A: Radio upper limits from GMRT observations
  3. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  4. EP250207B: GTC z-band Observations
  5. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  6. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  7. EP250207b: NOT optical counterpart candidate
  8. GRB 250211B: A long GRB detected by INTEGRAL
  9. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  10. Integral GRB250211.89: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  12. GRB 250207A: Fermi GBM Observation
  13. GRB 250206A: Fermi GBM Observation
  14. GRB 250205A / EP250205A: radio detection with the VLA
  15. EP250207b: Tentative z-band brightening source
  16. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  17. Konus-Wind detection of GRB 250207A
  18. Konus-Wind detection of GRB 250206A
  19. GRB 250210A: SVOM/GRM observation of a long burst
  20. EP250207b: Liverpool Telescope possible optical counterpart
  21. EP250207b: Global MASTER-Net observations report
  22. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
  24. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  25. GRB 250207A: Skynet optical afterglow observations
  26. GRB 241128A: VIRT Optical Upper Limit
  27. EP250207b: Gemini GMOS-N z-band observations
  28. GRB 250210A: AstroSat CZTI detection
  29. EP250207b: a new X-ray transient detected by Einstein Probe
  30. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  31. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  32. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  33. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  34. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  35. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  36. GRB 250207A: 1.3m DFOT Optical observations
  37. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  38. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  39. GRB 250129A: GRANDMA Continued Afterglow Detection
  40. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  41. GRB 250205A: 1.3m DFOT optical upper limit
  42. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  43. GRB 250207B: Swift-XRT observations
  44. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  45. LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
  46. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  47. EP250207a: EP-WXT detection and XRT follow-up observation
  48. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  49. GRB 250207A: Swift-XRT refined Analysis
  50. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  51. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  52. GRB 250207A: Enhanced Swift-XRT position
  53. 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%
  54. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  55. GRB 250207A: REM IR afterglow detection
  56. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  57. Konus-Wind detection of GRB 250204B
  58. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  59. GRB 250207A: REM optical afterglow detection
  60. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  62. GRB 250207A: Swift/UVOT Detection
  63. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  64. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  65. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  66. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  67. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  68. GRB 250129A: Continued AbAO and Mondy optical observations
  69. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  70. The EP-WXT trigger 01709131347 is likely a flaring star
  71. The EP-WXT trigger 01709131332 is likely a flaring star
  72. The EP-WXT trigger 01709131290 is likely a flaring star
  73. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  74. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  75. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  76. GRB 250207A: Swift detection of a burst with optical counterpart
  77. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  78. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  79. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  80. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  81. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  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. Konus-Wind detection of GRB 250201A
  97. IPN triangulation of GRB 250201A
  98. Konus-Wind detection of GRB 250202B
  99. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  100. IPN triangulation of GRB 250202B

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