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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"

24653 results found.

  1. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  2. GRB 240910A: LBT optical observations
  3. GRB 241006A: Swift-XRT refined Analysis
  4. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  5. GRB 241006A: PRIME near-infrared upper limits
  6. GRB 241006A: Swift/UVOT Upper Limits
  7. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  8. GRB 241001A: Swift-XRT afterglow detection
  9. GRB 241006A: Enhanced Swift-XRT position
  10. GRB 241006A: Swift detection of a burst
  11. GRB 240930B: SVOM/C-GFT optical upper limit
  12. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  13. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  14. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  15. GRB 241002B: Fermi GBM Observation
  16. GRB 241002B: Swift-XRT observations
  17. GRB 241002C: SVOM/C-GFT optical upper limit
  18. GRB 241002A: Swift-BAT refined analysis
  19. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  20. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  21. GRB 241002B: PRIME near-infrared detection
  22. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  23. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  24. IPN triangulation of GRB 240930B / EP 240930a
  25. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  26. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  27. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  28. GRB 241002C : MITSuME Akeno optical upper limits
  29. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  30. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  31. GRB241001A: REM optical/NIR upper limits
  32. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  33. GRB 241002A: Swift/UVOT Upper Limits
  34. EP240930a: Liverpool Telescope observations
  35. GRB 241002A: Swift-XRT refined Analysis
  36. GRB 241002A: LCOGT Optical Upper Limits
  37. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  38. GRB 241001A: Swift/UVOT Detection
  39. GRB 240929A: Liverpool Telescope prompt followup observations
  40. GRB 241001A: Swift-XRT observations
  41. GRB241001A: optical afterglow candidate
  42. GRB 241002A: Enhanced Swift-XRT position
  43. GRB 241001A: BOOTES-6/DPRT optical upper limit
  44. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  45. GRB 241002A: Swift detection of a burst
  46. LIGO/Virgo/KAGRA S240930du: Updated Sky localization
  47. GRB 240930B: Fermi GBM Observation
  48. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  49. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  50. EP240930a: EP-WXT detection of a fast X-ray transient
  51. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  52. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  53. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  54. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  55. AMON NuEM 240926A: Swift XRT Follow-up
  56. GRB 240929A : Leavitt Observatory optical upper limit
  57. GRB 240825A: LBT optical observations
  58. GRB 240928A: SVOM/GRM observation
  59. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  60. Fermi trigger No 749339671: Global MASTER-Net observations report
  61. GRB 240929A long GRB detected by INTEGRAL
  62. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  63. Swift Trigger 1256950 is probably not a GRB
  64. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  66. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  67. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  68. GRB 240926A: SVOM/GRM observation
  69. Konus-Wind detection of GRB 240905B
  70. EP240919a / GRB 240919A: SVOM/VT upper limit
  71. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  72. EP240918b and EP240918c: EP-FXT follow-up observations
  73. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  74. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  75. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  76. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  77. GRB 240905B: VZLUSAT-2 detection
  78. LIGO/Virgo/KAGRA S240922df: Updated Sky localization
  79. LIGO/Virgo/KAGRA S240920dw: Updated Sky localization
  80. LIGO/Virgo/KAGRA S240921cw: Updated Sky localization
  81. LIGO/Virgo/KAGRA S240924a: Updated Sky localization
  82. LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification
  83. LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification
  84. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  87. GRB 240918B: AstroSat CZTI detection
  88. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  89. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  90. EP240913A/GRB 240913C: AbAO optical upper limit
  91. EP240919a / GRB 240919A: Mondy optical upper limit
  92. EP240913a/GRB 240913C: 1.6m Mephisto observations
  93. EP240918a: SVOM/VT upper limit
  94. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  95. EP240919a / GRB 240919A: REM optical and NIR upper limits
  96. EP240918b and EP240918c: Optical upper limits with Kinder observations
  97. GRB 240414A: further radio observations with the VLA
  98. EP240919a: Optical upper limit with Kinder observations
  99. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  100. GRB 240910A: radio detection with the VLA

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