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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"

21940 results found.

  1. GRB 250109A / EP250109a: Mephisto optical upper limits
  2. EP250108a: Mephisto detection
  3. EP250111a: Mondy optical observation
  4. EP250108a / AT 2025kg: LCO optical observations
  5. EP250111a: Swift/XRT detection and fading
  6. EP250111a: NOT likely optical counterpart
  7. GRB 250101B: Fermi GBM Observation
  8. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  9. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  10. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  11. Konus-Wind detection of GRB 250107C
  12. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  13. GRB 250101A: CMO RC-500 optical observations
  14. EP250108a: EP-FXT follow-up observation
  15. EP250108a: NOT optical observations
  16. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  17. GRB 250109a: GMG Optical Upper Limit
  18. EP250109a: Swift/UVOT non-detection
  19. Konus-Wind detection of GRB 250107D (short/hard)
  20. IPN triangulation of GRB 250107D (short/hard)
  21. EP250108a: Liverpool Telescope likely optical counterpart
  22. GRB 250108B: 1.3m DFOT upper limit
  23. GRB 250108B: REM optical/NIR upper limits
  24. EP250109a: Global MASTER-Net observations report
  25. GRB 250101A: Terskol K-800 optical observations
  26. EP250109a: Swift/XRT non-detection
  27. GRB 250108A: Swift/UVOT Upper Limits
  28. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  29. GRB 250108A: NOT optical upper limit
  30. EP250108a: EP-WXT detection of an X-ray transient
  31. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  32. GRB 250103A: 1.6m Mephisto optical observations
  33. GRB 250108A: Swift-XRT afterglow detection
  34. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  35. GRB 250108B: Swift/UVOT Upper Limits
  36. GRB 250103A: Swift-XRT afterglow detection
  37. GRB 250108B: Enhanced Swift-XRT position
  38. GRB 250108B: Swift detection of a burst
  39. GRB 250108A: SVOM detection of a soft long burst
  40. GRB 241228B: Fermi-LAT detection
  41. GRB 250101A: J band upper limit by SYSU 80cm telescope
  42. EPWXT01709129925: Xinglong optical observations
  43. GRB 250106A: NOT optical observations
  44. GRB 250103B: REM optical/NIR upper limits
  45. GRB 250101A: REM optical/NIR counterpart detection
  46. GRB 250106A: SVOM detection of a long burst
  47. GRB 250103B: Swift-XRT refined Analysis
  48. GRB 250103B: LCO/1m optical afterglow candidate detection
  49. GRB 250103A: Bassano Bresciano Observatory upper limit
  50. GRB 250101A: 1.3m DFOT optical afterglow detection
  51. GRB 241229A: 1.3m DFOT upper limit
  52. GRB 241228B: 1.3m DFOT Optical observations
  53. GRB 241228A: 1.3m DFOT upper limit
  54. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  55. GRB 250103A: Montarrenti Observatory optical detection
  56. GRB 250101A: further LCOGT optical afterglow observations
  57. GRB 250103A: TSHAO optical upper limit
  58. GRB 250103A: Fermi GBM Observation
  59. GRB 250103B: LCOGT Optical Upper Limit
  60. EP250101a: Liverpool Telescope optical upper limit
  61. GRB 250101a: Liverpool Telescope optical follow-up
  62. GRB 250103B: SVOM detection of a long burst
  63. GRB 250103B: Swift detection of a burst
  64. GRB 250103A: Xinglong 2.16m Optical Candidate
  65. GRB 250101B: SVOM/GRM observation
  66. GRB 250103A: GOTO optical upper limit
  67. GRB 250103A: SVOM/C-GFT optical upper limit
  68. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  69. EP241231b: optical upper limit with the Liverpool Telescope
  70. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  71. GRB 250103A: SVOM detection of a long burst
  72. EP250101a: Xinglong optical upper limit
  73. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  74. GRB 250101A: further SAO RAS optical observations
  75. GRB 250101A: LCO optical counterpart detection
  76. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  77. GRB 250101A: Swift/UVOT Detection
  78. GRB 250101A: 1.6m Mephisto multi-band optical followup
  79. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  80. GRB 250101A: LCOGT optical afterglow detection
  81. GRB 250101A: OASDG optical observations
  82. GRB 250101A: BOOTES-4/MET optical afterglow detection
  83. GRB 250101A: AKO Optical Afterglow Detection
  84. GRB 250101A: SAO RAS optical observations
  85. GRB 250101A: Enhanced Swift-XRT position
  86. GRB 250101A: SVOM/C-GFT early optical observations
  87. GRB 250101A : GIT optical detection
  88. GRB 250101A: GMG Optical Observation
  89. GRB 250101A: Swift detection of a burst with an optical counterpart
  90. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  91. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  92. GRB 241229B: Continued CrAO ZTSh observations
  93. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  94. GRB 241229A: EP-FXT X-ray afterglow confirmation
  95. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  96. GRB 241229B: SVOM/GRM observation
  97. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  98. EP241217A: J band upper limit by SYSU 80cm telescope
  99. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  100. GRB 241229B: SAO RAS optical upper limit

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