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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

32485 results found.

  1. GRB 250103B:SVOM/VT optical counterpart
  2. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  3. GRB 250103A: Montarrenti Observatory optical detection
  4. GRB 250101A: further LCOGT optical afterglow observations
  5. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  6. GRB 250103A: NOT optical observations
  7. GRB 250103A: TSHAO optical upper limit
  8. GRB 250103A: Fermi GBM Observation
  9. GRB 250103B: LCOGT Optical Upper Limit
  10. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  11. Swift GRB 250103B: Global MASTER-Net observations report
  12. GRB 250103A: SVOM/VT optical counterpart confirmation
  13. EP250101a: Liverpool Telescope optical upper limit
  14. GRB 250103A: Swift ToO observations
  15. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  16. GRB 250101a: Liverpool Telescope optical follow-up
  17. GRB 250103B: SVOM detection of a long burst
  18. GRB 250103A: Xinglong 2.16m Optical Candidate
  19. Fermi GRB 250102A: Global MASTER-Net observations report
  20. GRB 250101B: SVOM/GRM observation
  21. GRB 250103A: GOTO optical upper limit
  22. GRB 250103A: SVOM/C-GFT optical upper limit
  23. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  24. EP241231b: optical upper limit with the Liverpool Telescope
  25. EP250101a: Xinglong optical upper limit
  26. GRB 250101A: Swift-BAT refined analysis
  27. GRB 250101A: further SAO RAS optical observations
  28. GRB 250101A: LCO optical counterpart detection
  29. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  30. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  31. GRB 250101A: Swift/UVOT Detection
  32. GRB 250101A: 1.6m Mephisto multi-band optical followup
  33. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  34. GRB 250101A: LCOGT optical afterglow detection
  35. GRB 250101A: OASDG optical observations
  36. Fermi GRB 250101B: Global MASTER-Net observations report
  37. GRB 250101A: SAO RAS observations of optical brightening
  38. GRB 250101A: AKO Optical Afterglow Detection
  39. GRB 250101A: SAO RAS optical observations
  40. LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
  41. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  42. GRB 250101A: SVOM/C-GFT early optical observations
  43. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  44. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  45. GRB 250101A: Nanshan/HMT optical observations
  46. GRB 250101A : GIT optical detection
  47. GRB 250101A: GMG Optical Observation
  48. GRB 241217a/EP241217b: ATCA Radio Detection
  49. EP241217a: VLA Radio Detection

  50. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  51. GRB 241229B: Continued CrAO ZTSh observations
  52. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  53. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  54. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  55. GRB 241229A: EP-FXT X-ray afterglow confirmation
  56. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  57. GRB 241229B: SVOM/GRM observation
  58. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  59. EP241217A: J band upper limit by SYSU 80cm telescope
  60. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  61. GRB 241229B: SAO RAS optical upper limit
  62. GRB 241228B: SAO RAS optical observations
  63. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  64. GRB 241229A: SAO RAS optical observations
  65. GRB 241229B: SVOM/VT optical candidate
  66. GRB 241229A: Swift-XRT observations
  67. Konus-Wind detection of GRB 241228A
  68. GRB 241229A: EP-FXT afterglow candidates
  69. EP240702a: 7DT Optical upper limits
  70. GRB 240606B: 7DT Optical upper limits
  71. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  72. GRB 241229B: Swift-BAT refined analysis
  73. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  74. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  75. GRB241229B: UVOT upper limits
  76. GRB 241228B: D50 optical detection
  77. GRB 241228B: Fermi GBM Observation
  78. GRB 241229B: Fermi GBM Observation
  79. GRB 241229A: Swift ToO observations
  80. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  81. GRB 241228A: Mondy optical afterglow observations
  82. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  83. Swift GRB 241229B: Global MASTER-Net observations report
  84. GRB 241229A: GOTO optical upper limits
  85. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  86. GRB 241228A: NOT optical upper limits
  87. GRB 241228B: LCO optical observation
  88. GRB 241228A: Swift-BAT refined analysis
  89. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  90. Fermi GRB 241228B: Global MASTER-Net observations report
  91. GRB 241228A: Fermi GBM Observation
  92. GRB241228B: GROWTH-India Telescope optical observations
  93. Swift GRB 241228A: Global MASTER-Net observations report
  94. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  95. GRB 241228B: GOTO24jmz optical follow-up observations
  96. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  97. GRB 241228A: GROWTH-India telescope optical upper limit
  98. GRB 241228B: Swift ToO observations
  99. GRB 241228B: TRT optical counterpart confirmation
  100. GRB 241228A: Swift/UVOT Upper Limits

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