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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"

23603 results found.

  1. IPN triangulation of GRB 250107D (short/hard)
  2. IPN triangulation of GRB 250107C
  3. EP250108a: Liverpool Telescope likely optical counterpart
  4. GRB 250108B: 1.3m DFOT upper limit
  5. GRB 250108B: REM optical/NIR upper limits
  6. EP250109a: SVOM/VT optical candidate
  7. GRB 250101A: Terskol K-800 optical observations
  8. EP250109a: GOTO optical upper limits
  9. EP250109a: Swift/XRT non-detection
  10. GRB 250108A: Swift/UVOT Upper Limits
  11. EP250109a: EP-WXT detection of an X-ray transient
  12. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  13. GRB 250108A: NOT optical upper limit
  14. EP250108a: EP-WXT detection of an X-ray transient
  15. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  16. GRB 250103A: 1.6m Mephisto optical observations
  17. GRB 250108A: Swift-XRT afterglow detection
  18. GRB 250108A:SVOM/VT optical candidate
  19. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  20. GRB 250108B: Swift/UVOT Upper Limits
  21. GRB 250103A: Swift-XRT afterglow detection
  22. GRB 250108B: Enhanced Swift-XRT position
  23. GRB 250108B: Swift detection of a burst
  24. GRB 250101A: J band upper limit by SYSU 80cm telescope
  25. EPWXT01709129925: Xinglong optical observations
  26. GRB 250106A: NOT optical observations
  27. GRB 250103B: REM optical/NIR upper limits
  28. GRB 250101A: REM optical/NIR counterpart detection
  29. GRB 250106A: Swift-XRT observations
  30. GRB 250106A: SVOM/VT optical candidate
  31. GRB 241229A: SVOM/VT optical upperlimit
  32. GRB 250103B: Swift-XRT refined Analysis
  33. GRB 250103B: LCO/1m optical afterglow candidate detection
  34. GRB 250103A: Bassano Bresciano Observatory upper limit
  35. GRB 250103A: Swift-XRT observations
  36. GRB 250101A: 1.3m DFOT optical afterglow detection
  37. GRB 241229A: 1.3m DFOT upper limit
  38. GRB 241228B: 1.3m DFOT Optical observations
  39. GRB 241228A: 1.3m DFOT upper limit
  40. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  41. GRB 250103A: Montarrenti Observatory optical detection
  42. GRB 250101A: further LCOGT optical afterglow observations
  43. GRB 250103A: TSHAO optical upper limit
  44. GRB 250103B: LCOGT Optical Upper Limit
  45. EP250101a: Liverpool Telescope optical upper limit
  46. GRB 250101a: Liverpool Telescope optical follow-up
  47. GRB 250103B: Swift detection of a burst
  48. GRB 250103A: Xinglong 2.16m Optical Candidate
  49. GRB 250101B: SVOM/GRM observation
  50. GRB 250103A: GOTO optical upper limit
  51. GRB 250103A: SVOM/C-GFT optical upper limit
  52. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  53. EP241231b: optical upper limit with the Liverpool Telescope
  54. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  55. GRB 250103A: SVOM detection of a long burst
  56. EP250101a: Xinglong optical upper limit
  57. GRB 250101A: further SAO RAS optical observations
  58. GRB 250101A: LCO optical counterpart detection
  59. GRB 250101A: Swift/UVOT Detection
  60. GRB 250101A: 1.6m Mephisto multi-band optical followup
  61. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  62. GRB 250101A: LCOGT optical afterglow detection
  63. GRB 250101A: OASDG optical observations
  64. GRB 250101A: AKO Optical Afterglow Detection
  65. GRB 250101A: SAO RAS optical observations
  66. GRB 250101A: Enhanced Swift-XRT position
  67. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  68. GRB 250101A: SVOM/C-GFT early optical observations
  69. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  70. GRB 250101A : GIT optical detection
  71. GRB 250101A: GMG Optical Observation
  72. GRB 250101A: Swift detection of a burst with an optical counterpart
  73. EP241217a: VLA Radio Detection

  74. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  75. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  76. GRB 241229B: Continued CrAO ZTSh observations
  77. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  78. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  79. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  80. GRB 241229B: SVOM/GRM observation
  81. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  82. EP241217A: J band upper limit by SYSU 80cm telescope
  83. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  84. GRB 241229B: SAO RAS optical upper limit
  85. GRB 241228B: SAO RAS optical observations
  86. GRB 241229B: SVOM/VT optical candidate
  87. GRB 241229A: EP-FXT afterglow candidates
  88. EP240702a: 7DT Optical upper limits
  89. GRB 240606B: 7DT Optical upper limits
  90. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  91. GRB 241229B: Swift-BAT refined analysis
  92. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  93. GRB241229B: UVOT upper limits
  94. GRB 241228B: Swift-XRT afterglow detection
  95. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  96. GRB 241228A: Mondy optical afterglow observations
  97. GRB 241229A: GOTO optical upper limits
  98. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  99. GRB 241228A: NOT optical upper limits
  100. GRB 241228B: LCO optical observation

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