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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"

8474 results found.

  1. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  2. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  3. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  4. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  5. GRB 241229A: SAO RAS optical observations
  6. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  7. GRB 241229B: SVOM/VT optical candidate
  8. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  10. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  11. GRB 241229A: Swift ToO observations
  12. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  13. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  14. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  15. GRB 241228B: GOTO24jmz optical follow-up observations
  16. GRB 241228B: Swift ToO observations
  17. GRB 241228B: TRT optical counterpart confirmation
  18. GRB 241228B: GOTO possible optical counterpart candidate
  19. GRB 241228A: Swift detection of a burst
  20. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  21. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  22. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  24. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  25. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  26. GRB 241223A: Swift ToO observations
  27. EP241217a: 1.6m Mephisto multi-band optical observations
  28. EP241217a: optical upper limit with the Liverpool Telescope
  29. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  30. GRB 241218A: Swift detection of a burst
  31. GRB 241217A: LCO optical upper limit
  32. GRB 241217A: GRANDMA/TAROT optical upperlimits
  33. EP241217A: Non-detection from Fermi-GBM Observations
  34. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  35. EP241217a: Kinder optical follow-up observations
  36. GRB 241215A: Mondy AZT-33IK optical observations
  37. The EP-WXT trigger 01709128948 is likely a flaring star
  38. GRB 241215A: Montarrenti Observatory optical upper limit
  39. GRB 241213A: SVOM/VT optical candidate
  40. GRB 241213B: Tiled Swift observations
  41. GRB 241212A: Swift ToO observations
  42. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
  43. GRB 241213A: Swift detection of a burst
  44. GRB 241209B: GRANDMA/TRT upper limit
  45. GRB 241207A: TSHAO Zeiss-1000 optical observations
  46. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  47. LIGO/Virgo/KAGRA S241210cw: Updated Sky localization
  48. LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
  49. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  52. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  53. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  54. GRB 241209A: GRANDMA/TAROT upper limit
  55. GRB 241209B: Swift ToO observations
  56. GRB 241209A: VLT/X-shooter spectroscopy
  57. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  58. GRB 241209A: Swift detection of a short burst
  59. GRB 241207C: Tiled Swift observations
  60. EP241201a: 1.6m Mephisto Optical Upper Limits
  61. EP241202b: KAIT optical upper limit
  62. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  63. EP241202b: Upper limits from Fermi-GBM Observations
  64. EP241202b: Kinder optical counterpart candidate
  65. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  66. Konus-Wind detection of GRB 241130A
  67. EP241201a: NOT optical observations
  68. GRB 241130A: EIRSAT-1 GMOD Detection
  69. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  70. EP241201a: Kinder optical counterpart candidate
  71. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  72. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  73. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  75. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  76. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  77. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  78. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  79. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  80. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  81. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  83. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  84. EP241126a: WFST Observations
  85. GRB 241127A: Swift detection of a burst with an optical counterpart
  86. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  87. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  88. IceCube-241127A: IceCube observation of a high-energy neutrino candidate track-like event
  89. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  90. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  91. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  92. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  93. LIGO/Virgo/KAGRA S241126dm: Retraction of GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  95. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  96. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  97. GRB 241026A: radio detection with the VLA
  98. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  99. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  100. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event

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