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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').
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"

20819 results found.

  1. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  2. IceCube-241006A: No candidates from the Zwicky Transient Facility
  3. GRB 241006A: GRANDMA optical upper limits
  4. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  5. GRB 240910A: LBT optical observations
  6. GRB 241006A: PRIME near-infrared upper limits
  7. GRB 241006A: Swift/UVOT Upper Limits
  8. GRB 241006A: SVOM/VT follow-up and optical upper limit
  9. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  10. GRB 241001A: Swift-XRT afterglow detection
  11. GRB 241006A: Enhanced Swift-XRT position
  12. GRB 241006A: Swift detection of a burst
  13. GRB 240930B: SVOM/C-GFT optical upper limit
  14. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  15. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  16. GRB 241002B: Swift-XRT observations
  17. GRB 241002C: SVOM/C-GFT optical upper limit
  18. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  19. Konus-Wind detection of GRB 240926A
  20. GRB 241002B: PRIME near-infrared detection
  21. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  22. IPN triangulation of GRB 240930B / EP 240930a
  23. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  24. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  25. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  26. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  27. GRB 241002C : MITSuME Akeno optical upper limits
  28. GRB241001A: REM optical/NIR upper limits
  29. GRB 241002A: Swift/UVOT Upper Limits
  30. EP240930a: Liverpool Telescope observations
  31. GRB 241002A: LCOGT Optical Upper Limits
  32. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  33. GRB 241001A: Swift/UVOT Detection
  34. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  35. GRB 240929A: Liverpool Telescope prompt followup observations
  36. GRB 241001A: Swift-XRT observations
  37. GRB241001A: optical afterglow candidate
  38. GRB 241002A: Enhanced Swift-XRT position
  39. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  40. GRB 241002A: Swift detection of a burst
  41. GRB 240930B: Fermi GBM Observation
  42. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  43. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  44. EP240930a: EP-WXT detection of a fast X-ray transient
  45. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  46. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  48. AMON NuEM 240926A: Swift XRT Follow-up
  49. GRB 240929A : Leavitt Observatory optical upper limit
  50. Fermi GRB 240930B: Global MASTER-Net observations report
  51. IPN triangulation of GRB 240926A
  52. GRB 240825A: LBT optical observations
  53. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  54. Swift Trigger 1256950 is probably not a GRB
  55. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  56. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  57. EP240919a / GRB 240919A: SVOM/VT upper limit
  58. EP240918b and EP240918c: EP-FXT follow-up observations
  59. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  60. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  61. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  62. IPN triangulation of GRB 240918B
  63. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  64. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  65. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo S240919bn: GOTO optical upper limits
  67. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  68. GRB 240918B: AstroSat CZTI detection
  69. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  70. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  71. EP240913A/GRB 240913C: AbAO optical upper limit
  72. EP240919a / GRB 240919A: Mondy optical upper limit
  73. EP240913a/GRB 240913C: 1.6m Mephisto observations
  74. EP240918a: SVOM/VT upper limit
  75. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  76. EP240919a / GRB 240919A: REM optical and NIR upper limits
  77. EP240918b and EP240918c: Optical upper limits with Kinder observations
  78. GRB 240414A: further radio observations with the VLA
  79. EP240919a: Optical upper limit with Kinder observations
  80. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  81. GRB 240910A: radio detection with the VLA
  82. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  83. EP240919a: NOT and Gemini optical observations
  84. EP240919a: GOTO optical upper limits
  85. EP240919a: JinShan optical upper limits
  86. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  87. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  88. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  89. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  90. GRB 240910A: further Swift observations and confirmation of afterglow
  91. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  92. EP240918a: JinShan optical upper limits
  93. EP240918a: Optical upper limits with Kinder observations
  94. EP240918a: GMG Optical Upper Limit
  95. EP240918a: an X-ray transient detected by Einstein Probe
  96. GRB 240916A: NOT optical observation
  97. IPN triangulation of GRB 240913C / EP 240913a
  98. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  99. GRB 240821A: radio observation with the VLA
  100. GRB 240916A: Swift-XRT afterglow detection

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