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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"

26672 results found.

  1. GRB 250805A: Swift-XRT refined Analysis
  2. GRB 250804B: Swift-XRT observations
  3. GRB 250805A: Enhanced Swift-XRT position
  4. GRB 250805A: TRT optical upper limits
  5. GRB 250805A: Swift-XRT observations
  6. GRB 250804B: SVOM/GRM observation of a short burst
  7. EP250802a: additional Liverpool Telescope upper limits
  8. EP250730a: SVOM/VT optical upper limit
  9. EP250802a: Liverpool Telescope optical upper limits
  10. EP250802a: GROWTH-India Telescope optical upper limit
  11. EP250802a: Einstein Probe detection of an X-ray transient
  12. The EP-WXT trigger 01709198251 is likely a flaring star
  13. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  14. The EP-WXT trigger 01709198202 is likely a flaring star
  15. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  16. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
  17. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  18. EP250711a: CrAO and Assy optical observations
  19. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  20. EP250730a: COLIBRÍ optical upper limit
  21. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  22. EP250730a: Einstein Probe detection of an X-ray transient
  23. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  24. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  25. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  28. GRB 250727A: EP-FXT follow-up observation
  29. GRB 250725A: PRIME near-infrared observations
  30. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  31. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  32. GRB 250728A: Swift-XRT observations
  33. GRB 250727A: SVOM/ECLAIRs refined analysis
  34. EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  35. GRB 250728A: COLIBRÍ optical upper limit
  36. GRB 250728A: Fermi GBM Observation
  37. GRB 250727A: AST3-2 Upper limit
  38. GRB 250727A: EP-FXT counterpart detection
  39. GRB250727A: SVOM/VT optical upper limit
  40. GRB 250727A: Swift-XRT observations
  41. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
  44. GRB 250727A: SVOM detection of a burst
  45. The EP-WXT trigger 01709195487 is likely a flaring star
  46. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  47. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  48. GRB 250725A: Swift-XRT refined Analysis
  49. GRB 250725A: Fermi GBM Observation
  50. GRB 250725A: Swift-BAT refined analysis
  51. Konus-Wind detection of GRB 250725A
  52. GRB 250725A: SVOM/GRM observation
  53. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  54. GRB 250725A: Swift/UVOT Upper Limits
  55. GRB 250725A: SVOM/VT optical candidate
  56. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  57. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  58. LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
  59. GRB 250725A: Enhanced Swift-XRT position
  60. GRB 250725A: Swift detection of a burst
  61. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  62. SVOM J195836+32283 is not a real source
  63. EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
  64. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  65. GRB 250721A: Fermi GBM Observation
  66. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  67. GRB 250721A: Swift-XRT observations
  68. GRB 250713A : SVOM/ECLAIRs refined analysis
  69. GRB 250717B: SVOM/GRM observation
  70. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  71. GRB 250717B: COLIBRÍ optical upper limit
  72. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  73. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  74. GRB 270713A: Kitab and AbAO Optical Observations
  75. GRB 250717B: Fermi GBM Observation
  76. GRB 250716A: Swift-XRT afterglow detection
  77. GRB 250716A: Fermi GBM Observation
  78. GRB 250714A: SVOM/GRM observation
  79. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  80. GRB 250713A: Mephisto optical upper limits
  81. GRB 250713A: SVOM/VT optical upper limit
  82. GRB 250713A: NOT optical upper limits
  83. GRB 250713A: OHP/T193 upper limit
  84. GRB 250713A: SVOM/C-GFT upper limit
  85. GRB 250706B/C: 7DT Follow-up Observations
  86. GRB 250713A: Swift-XRT observations
  87. GRB 250713A: EP-FXT counterpart detection
  88. EP250711a: COLIBRÍ continuous optical observations
  89. GRB 250706A: Swift-BAT refined analysis
  90. GRB 250713A: JinShan optical upper limits
  91. GRB 250713A: SVOM detection of a long burst
  92. GRB 250711A: DDOTI Optical Upper Limit
  93. LIGO/Virgo/KAGRA S250712cd: Identification of a GW compact binary merger candidate
  94. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  95. GRB 250711A: SVOM/GRM observation
  96. EP250711a: NOT optical counterpart candidate
  97. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  98. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  99. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  100. GRB 250704A: GRANDMA observations

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