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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"

28247 results found.

  1. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  2. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  3. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  4. GRB 250119B: Fermi GBM Observation
  5. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  6. IPN triangulation of GRB 250117A (short)
  7. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  8. EP 250108A: Late-time optical observation by LCO
  9. LIGO/Virgo/KAGRA S250105bn: 1 counterpart neutrino candidate event from an IceCube neutrino search
  10. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  11. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  12. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  13. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  14. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  16. GRB 250117A: GECAM observation of a short burst
  17. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  18. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  19. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  20. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  22. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  23. EP250108a / AT2025kg: GMG Optical Observations
  24. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  25. GRB 241217A / EP241217B: radio detection with the VLA
  26. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  27. GRB 250114B: Swift-XRT afterglow detection
  28. EP250108a: MeerKAT radio upper limit
  29. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  30. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  31. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  32. IPN triangulation of GRB 250113A
  33. GRB 250114B: Liverpool Telescope optical upper limit
  34. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  35. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  36. GRB 250114B: Swift-XRT observations
  37. GRB 250114A: LCO optical counterpart detection.
  38. GRB 250114B: OHP/T193 optical upper limit
  39. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  40. GRB 250114A: Swift-XRT refined Analysis
  41. GRB 250114A: LCOGT optical afterglow i-band detection
  42. GRB 250114B : GIT optical upper limit
  43. EP250111a: SAO RAS optical upper limit
  44. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  45. GRB 250114B: a short GRB detected with INTEGRAL
  46. GRB 250114A: Enhanced Swift-XRT position
  47. GRB 250114A: REM detection of the optical and NIR counterpart
  48. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  49. Swift GRB250114A: Global MASTER-Net OT detection
  50. GRB 250114A: LCO optical observations
  51. GRB 250114A: TRT optical observations
  52. GRB 250114A: Swift detection of a burst with an optical counterpart
  53. GRB 250101A: Terskol Zeiss-2000 optical observations
  54. EP250108a / AT 2025kg: SAO RAS optical observations
  55. EP241021a: SMA radio observation
  56. GRB 250113A: SVOM/GRM observation of a long burst
  57. GRB 250107A: VZLUSAT-2 detection
  58. EP250109b: optical upper limits with the Liverpool Telescope
  59. GRB 250106A: Swift-XRT afterglow detection
  60. EP250111a: KAIT optical observations
  61. GRB 250109A / EP250109a: Mephisto optical upper limits
  62. EP250108a: Mephisto detection
  63. EP250111a: Mondy optical observation
  64. EP250108a / AT 2025kg: LCO optical observations
  65. EP250108a / AT 2025kg: Swift UVOT detections
  66. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  67. EP250111a: NOT likely optical counterpart
  68. GRB 250101B: Fermi GBM Observation
  69. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  70. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  71. GRB 250108A: Swift/XRT afterglow fading
  72. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  73. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  74. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  75. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  76. GRB 250101A: CMO RC-500 optical observations
  77. GRB 250109A: Fermi GBM Observation
  78. EP250108a: NOT optical observations
  79. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  80. GRB 250109a: GMG Optical Upper Limit
  81. EP250109a: Swift/UVOT non-detection
  82. IPN triangulation of GRB 250107D (short/hard)
  83. EP250108a: Liverpool Telescope likely optical counterpart
  84. GRB 250108B: Swift-BAT refined analysis
  85. GRB 250108B: 1.3m DFOT upper limit
  86. GRB 250108B: REM optical/NIR upper limits
  87. GRB 250101A: Terskol K-800 optical observations
  88. EP250109a: Swift/XRT non-detection
  89. GRB 250108A: Swift/UVOT Upper Limits
  90. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  91. GRB 250108A: NOT optical upper limit
  92. EP250108a: EP-WXT detection of an X-ray transient
  93. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  94. GRB 250108B: Swift-XRT refined Analysis
  95. GRB 250103A: 1.6m Mephisto optical observations
  96. GRB 250108A: Swift-XRT afterglow detection
  97. GRB 250108A:SVOM/VT optical candidate
  98. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  99. GRB 250108B: Swift/UVOT Upper Limits
  100. GRB 250103A: Swift-XRT afterglow detection

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