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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"

24699 results found.

  1. GRB 241217A / EP241217b: NOT optical upper limits
  2. GRB 241218A: REM optical upper limit
  3. GRB 241217A/EP241217b: REM optical/NIR upper limits
  4. EP241217a: REM optical/NIR upper limits
  5. GRB 241217a: Liverpool Telescope optical follow-up
  6. EP241217a: Liverpool Telescope optical follow-up
  7. GRB 241218A: Swift-XRT refined Analysis
  8. EP241217a: NOT optical observations
  9. EP241217a: GROWTH-India Telescope optical observations
  10. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  11. EP241119a: 7DT Optical upper limits
  12. EP241217a: Xinglong optical follow-up observations
  13. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  14. GRB 241218A: LCOGT Optical Upper Limit
  15. GRB 241218A: Enhanced Swift-XRT position
  16. GRB 241217A: GMG Optical Upper Limit
  17. GRB 241218A: Swift detection of a burst
  18. GRB 241217A : SVOM/VT optical afterglow detection
  19. GRB 241217A: Swift-XRT afterglow detection
  20. GRB 241217A: LCO optical upper limit
  21. GRB 241217A: GRANDMA/TAROT optical upperlimits
  22. EP241217a: Swift-XRT Detection
  23. EP241217A: Non-detection from Fermi-GBM Observations
  24. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  25. EP241217a: Kinder optical follow-up observations
  26. EP241217A: LCO optical observations
  27. EP241217a: Gemini-North detection of the likely optical counterpart
  28. EP241217a: EP detection of an X-ray transient
  29. EP241107a: VLA Radio Observation
  30. GRB 241213A: Swift-BAT refined analysis
  31. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  32. GRB 241215A: Mondy AZT-33IK optical observations
  33. GRB 241212A: Swift-XRT observations
  34. GRB 241215A: Nanshan/HMT optical upper limit
  35. GRB 241215A: Montarrenti Observatory optical upper limit
  36. GRB 241215A: GROWTH-India telescope optical upper limit
  37. GRB 241215A: A long GRB detected by INTEGRAL
  38. Integral GRB241215.58: Global MASTER-Net observations report
  39. GRB 241213B: Swift-XRT observations
  40. GRB 241213A: Swift/UVOT Upper Limits
  41. GRB 241213A: Swift-XRT refined Analysis
  42. GRB 241212A: Fermi GBM detection
  43. EP241208a: NOT optical upper limits
  44. GRB 241213A: LCOGT Optical Upper Limits
  45. GRB 241213B: MAXI/GSC detection
  46. EP241213a: EP detection of An X-ray Transient
  47. GRB 241213A: REM optical/NIR upper limits
  48. GRB 241213A: Enhanced Swift-XRT position
  49. GRB241212A: OHP/T193 optical observations
  50. GRB 241213A: SAO RAS optical upper limit
  51. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
  52. GRB 241213A: Swift detection of a burst
  53. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  54. GRB 241212A: AstroSat CZTI detection
  55. GRB 241209B: GRANDMA/TRT upper limit
  56. GRB 241207A: TSHAO Zeiss-1000 optical observations
  57. GRB 241212A: SVOM detection of a bright long burst
  58. GRB 241207A: EIRSAT-1 GMOD Detection
  59. LIGO/Virgo/KAGRA S241210cw: Updated Sky localization
  60. LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
  61. GRB 241129A: Fermi GBM Observation
  62. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  63. GRB 241209D: REM optical/NIR upper limits
  64. GRB 241209B: Swift-XRT afterglow detection
  65. GRB 241209C: Fermi GBM Observation
  66. GRB 241209A: Swift-XRT refined Analysis
  67. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  68. EP241208a: Optical upper limit with Kinder observations
  69. GRB 241209B: SVOM/VT afterglow detection
  70. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  71. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  72. GRB 241207B: Fermi GBM Observation
  73. GRB 241209D: Swift-XRT refined Analysis
  74. GRB 241209D: Fermi GBM Observation
  75. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  76. GRB 241209D: COLIBRÍ detection of the afterglow
  77. GRB 241209A: COLIBRÍ Optical Upper Limit
  78. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  79. GRB 241209A: GRANDMA/TAROT upper limit
  80. GRB 241209A: REM optical/NIR observations
  81. GRB 241209D: Enhanced Swift-XRT position
  82. GRB 241209D: Swift detection of a burst
  83. GRB 241209A: Enhanced Swift-XRT position
  84. GRB 241114B: cubesat Avion detection
  85. GRB 241209A: VLT optical observations
  86. GRB 241209A: GOTO optical upper limits
  87. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  88. EP241208a: EP detection of a fast X-ray transient
  89. GRB 241209A: Swift detection of a short burst
  90. Fermi GRB 241207B: Global MASTER-Net observations report
  91. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  92. GRB 241206A: DDOTI Upper Limit on the Afterglow
  93. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  94. GRB 241207C: MAXI/GSC detection
  95. EP241206a: EP detection of a fast X-ray transient
  96. GRB 241206A: Fermi GBM observation
  97. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  98. EP241201a: 1.6m Mephisto Optical Upper Limits
  99. GRB 241204A: COLIBRÍ Optical Upper Limit
  100. EP241202b: KAIT optical upper limit

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