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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').
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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"

28239 results found.

  1. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  2. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  3. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  4. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  5. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  6. GRB 250117A: GECAM observation of a short burst
  7. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  8. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  9. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  12. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  13. EP250108a / AT2025kg: GMG Optical Observations
  14. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  15. GRB 241217A / EP241217B: radio detection with the VLA
  16. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  17. GRB 250114B: Swift-XRT afterglow detection
  18. EP250108a: MeerKAT radio upper limit
  19. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  20. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  21. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  22. IPN triangulation of GRB 250113A
  23. GRB 250114B: Liverpool Telescope optical upper limit
  24. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  25. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  26. GRB 250114B: Swift-XRT observations
  27. GRB 250114A: LCO optical counterpart detection.
  28. GRB 250114B: OHP/T193 optical upper limit
  29. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  30. GRB 250114A: Swift-XRT refined Analysis
  31. GRB 250114A: LCOGT optical afterglow i-band detection
  32. GRB 250114B : GIT optical upper limit
  33. EP250111a: SAO RAS optical upper limit
  34. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  35. GRB 250114B: a short GRB detected with INTEGRAL
  36. GRB 250114A: Enhanced Swift-XRT position
  37. GRB 250114A: REM detection of the optical and NIR counterpart
  38. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  39. Swift GRB250114A: Global MASTER-Net OT detection
  40. GRB 250114A: LCO optical observations
  41. GRB 250114A: TRT optical observations
  42. GRB 250114A: Swift detection of a burst with an optical counterpart
  43. GRB 250101A: Terskol Zeiss-2000 optical observations
  44. EP250108a / AT 2025kg: SAO RAS optical observations
  45. EP241021a: SMA radio observation
  46. GRB 250113A: SVOM/GRM observation of a long burst
  47. GRB 250107A: VZLUSAT-2 detection
  48. EP250109b: optical upper limits with the Liverpool Telescope
  49. GRB 250106A: Swift-XRT afterglow detection
  50. EP250111a: KAIT optical observations
  51. GRB 250109A / EP250109a: Mephisto optical upper limits
  52. EP250108a: Mephisto detection
  53. EP250111a: Mondy optical observation
  54. EP250108a / AT 2025kg: LCO optical observations
  55. EP250108a / AT 2025kg: Swift UVOT detections
  56. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  57. EP250111a: NOT likely optical counterpart
  58. GRB 250101B: Fermi GBM Observation
  59. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  60. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  61. GRB 250108A: Swift/XRT afterglow fading
  62. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  63. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  64. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  65. EP-WXT trigger EP250108a:Xinglong optical follow-up observations
  66. GRB 250101A: CMO RC-500 optical observations
  67. GRB 250109A: Fermi GBM Observation
  68. EP250108a: NOT optical observations
  69. EP-WXT trigger EP250109a:Xinglong optical follow-up observations
  70. GRB 250109a: GMG Optical Upper Limit
  71. EP250109a: Swift/UVOT non-detection
  72. IPN triangulation of GRB 250107D (short/hard)
  73. EP250108a: Liverpool Telescope likely optical counterpart
  74. GRB 250108B: Swift-BAT refined analysis
  75. GRB 250108B: 1.3m DFOT upper limit
  76. GRB 250108B: REM optical/NIR upper limits
  77. GRB 250101A: Terskol K-800 optical observations
  78. EP250109a: Swift/XRT non-detection
  79. GRB 250108A: Swift/UVOT Upper Limits
  80. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  81. GRB 250108A: NOT optical upper limit
  82. EP250108a: EP-WXT detection of an X-ray transient
  83. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  84. GRB 250108B: Swift-XRT refined Analysis
  85. GRB 250103A: 1.6m Mephisto optical observations
  86. GRB 250108A: Swift-XRT afterglow detection
  87. GRB 250108A:SVOM/VT optical candidate
  88. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  89. GRB 250108B: Swift/UVOT Upper Limits
  90. GRB 250103A: Swift-XRT afterglow detection
  91. GRB 250108B: Enhanced Swift-XRT position
  92. GRB 250108B: Swift detection of a burst
  93. GRB 250107A: Fermi GBM Observation
  94. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  95. GRB 250106A: SVOM/VT 2nd optical deep observation
  96. GRB 250101A: J band upper limit by SYSU 80cm telescope
  97. EPWXT01709129925: Xinglong optical observations
  98. GRB 250106A: NOT optical observations
  99. LIGO/Virgo/KAGRA S250104v: Updated Sky localization
  100. GRB 250103B: REM optical/NIR upper limits

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