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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"

23687 results found.

  1. EP250109a: GOTO optical upper limits
  2. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  3. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  4. GRB 250108B: Swift-XRT refined Analysis
  5. GRB 250103A: 1.6m Mephisto optical observations
  6. GRB 250108A: Swift-XRT afterglow detection
  7. GRB 250108A:SVOM/VT optical candidate
  8. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  9. GRB 250103A: Swift-XRT afterglow detection
  10. GRB 250106A: SVOM/VT 2nd optical deep observation
  11. EPWXT01709129925: Xinglong optical observations
  12. GRB 250103B: REM optical/NIR upper limits
  13. GRB 250101A: REM optical/NIR counterpart detection
  14. GRB 250106A: Swift-XRT observations
  15. GRB 250106A: SVOM/VT optical candidate
  16. GRB 241229A: SVOM/VT optical upperlimit
  17. GRB 250103B: Swift-XRT refined Analysis
  18. GRB 250103A: Swift-XRT observations
  19. GRB 250103B：SVOM/VT optical counterpart
  20. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  21. GRB 250103A: Montarrenti Observatory optical detection
  22. GRB 250101A: further LCOGT optical afterglow observations
  23. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  24. GRB 250103A: SVOM/VT optical counterpart confirmation
  25. GRB 250103B: Swift detection of a burst
  26. GRB 250103A: GOTO optical upper limit
  27. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  28. GRB 250101A: Swift-BAT refined analysis
  29. GRB 250101A: further SAO RAS optical observations
  30. GRB 250101A: LCO optical counterpart detection
  31. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  32. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  33. GRB 250101A: Swift/UVOT Detection
  34. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  35. GRB 250101A: LCOGT optical afterglow detection
  36. GRB 250101A: OASDG optical observations
  37. GRB 250101A: SAO RAS observations of optical brightening
  38. GRB 250101A: BOOTES-4/MET optical afterglow detection
  39. GRB 250101A: SAO RAS optical observations
  40. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  41. GRB 250101A: GMG Optical Observation
  42. GRB 250101A: Swift detection of a burst with an optical counterpart
  43. EP241217a: VLA Radio Detection

  44. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  45. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  47. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  48. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  49. GRB 241229B: SAO RAS optical upper limit
  50. GRB 241228B: SAO RAS optical observations
  51. GRB 241229A: SAO RAS optical observations
  52. GRB 241229B: SVOM/VT optical candidate
  53. GRB 241229A: Swift-XRT observations
  54. Konus-Wind detection of GRB 241228A
  55. GRB 241229B: Swift-BAT refined analysis
  56. GRB241229B: UVOT upper limits
  57. GRB 241228B: D50 optical detection
  58. GRB 241228B: Swift-XRT afterglow detection
  59. GRB 241229B: Fermi GBM Observation
  60. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  61. GRB 241229A: GOTO optical upper limits
  62. GRB 241228B: LCO optical observation
  63. GRB 241228A: Swift-BAT refined analysis
  64. GRB 241229B: Swift detection of a burst
  65. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  66. GRB 241228B: GOTO24jmz optical follow-up observations
  67. GRB 241228B: TRT optical counterpart confirmation
  68. GRB 241228A: Swift-XRT refined Analysis
  69. GRB 241228A: Swift/UVOT Upper Limits
  70. GRB 241228B: GOTO possible optical counterpart candidate
  71. GRB 241228A: Swift detection of a burst
  72. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  73. GRB 241223A: GRBAlpha detection
  74. GRB 241212A: VZLUSAT-2 detection
  75. GRB 241029A: LCO optical observation
  76. GRB 241223A: Swift-XRT observations
  77. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  78. Fermi trigger No 756678579: Global MASTER-Net observations report
  79. EP241223a
  80. GRB 241223A: GOTO optical observations summary
  81. GRB 241105A: JWST photometric observations of the host galaxy
  82. EP241217a: e-MERLIN radio observations
  83. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  84. EP241021a: VLA radio detection
  85. EP241217a: 1.6m Mephisto multi-band optical observations
  86. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  87. GRB 241218A: Swift/UVOT Upper Limits
  88. GRB 241209B: EP-FXT afterglow detection
  89. Konus-Wind detection of GRB 241204A (short/hard)
  90. GRB 241218A: Swift-BAT refined analysis
  91. EP 241217a: Possible J-band detection with WINTER
  92. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  93. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  94. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  95. GRB 241218A: REM optical upper limit
  96. GRB 241217A/EP241217b: REM optical/NIR upper limits
  97. EP241217a: REM optical/NIR upper limits
  98. GRB 241218A: Swift-XRT refined Analysis
  99. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  100. EP241217a: Xinglong optical follow-up observations

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