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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"

32537 results found.

  1. GRB 241018A: SVOM/GRM observation
  2. GRB 241018A/sb24101802: Mephisto optical upper limit
  3. GRB 241017A/sb24101702: Mephisto optical upper limit
  4. GRB 241018A: Mondy optical upper limit
  5. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  6. GRB 241018A: GROWTH-India telescope optical upper limit
  7. GRB241018A: XingLong Optical Upper Limit
  8. GRB 241018A: REM optical/NIR upper limits
  9. GRB 241018A: NOT optical observations
  10. GRB 241017A: SVOM/VT follow-up and optical upper limit
  11. GRB 241018A: SVOM/VT follow-up and optical candidate
  12. GRB 241018A: LCO/0.4m optical upper limits
  13. GRB 241018A: Swift ToO observations
  14. GRB 241006A: VIRT Optical Upper Limit
  15. GRB 240727A: VIRT Optical Upper Limit
  16. GRB 241018A: X-ray afterglow candidate observed by MXT
  17. GRB 241016B: Fermi GBM Observations
  18. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  19. GRB 241001A: EP-FXT afterglow detection
  20. GRB 241017A: GROWTH-India Telescope optical upper limit
  21. GRB241017A: TOO Observations by SVOM/MXT
  22. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  23. GRB 241017A: J-band upper limit from WINTER
  24. GRB 241016B: SVOM/GRM observation
  25. GRB 241017A: Swift ToO observations
  26. Fermi GRB 241016B: Global MASTER-Net observations report
  27. Fermi GRB 241016A: Global MASTER-Net observations report
  28. GRB 241010A: Swift-BAT refined analysis
  29. GRB 241013B: Fermi GBM Observation
  30. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  31. GRB 241013A: Fermi GBM Observation
  32. GRB 240916A: radio detection with the VLA
  33. GRB241013A: REM observations
  34. GRB 241009A: LCO optical upper limits
  35. GRB 241013B: SVOM/GRM observation
  36. Fermi GRB 241013B: Global MASTER-Net observations report
  37. GRB 241013A: a long GRB detected by INTEGRAL
  38. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  39. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  40. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  41. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  42. GRB 241009A: GRANDMA optical upper limits
  43. GRB 241010A: JinShan optical observations and potential host galaxy
  44. GRB 241006A: ATCA Radio Upper Limits
  45. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  46. Swift GRB 241010A: Global MASTER-Net observations report
  47. GRB 241010A: J-band observations with WINTER
  48. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  49. Fermi GRB 241010B: Global MASTER-Net observations report
  50. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 241010A: LCO optical observations
  52. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  53. GRB 241006A: Swift-BAT refined analysis
  54. GRB 241009A: Swift ToO observations
  55. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  56. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  57. GRB 241008A: Fermi GBM Observation
  58. GRB 241008A: Fermi-LAT detection
  59. GRB 241002B: Swift-XRT afterglow detection
  60. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  61. GRB 241002A: NOT optical upper limits
  62. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  63. Fermi GRB 241008A: Global MASTER-Net observations report
  64. IceCube-241006A: No candidates from the Zwicky Transient Facility
  65. GRB 241006A: GRANDMA optical upper limits
  66. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  67. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  68. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  69. GRB 240910A: LBT optical observations
  70. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  71. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  72. GRB 241006A: PRIME near-infrared upper limits
  73. GRB 241006A: Swift/UVOT Upper Limits
  74. GRB 241006A: SVOM/VT follow-up and optical upper limit
  75. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  76. GRB 240930B: SVOM/C-GFT optical upper limit
  77. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  78. GRB 240930B / EP 240930a: SVOM/GRM observation
  79. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  80. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  81. GRB 241002B: Fermi GBM Observation
  82. GRB 241002B: Swift-XRT observations
  83. GRB 241002C: SVOM/C-GFT optical upper limit
  84. GRB 241002A: Swift-BAT refined analysis
  85. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  86. GRB 241002B: Swift ToO observations
  87. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  88. Konus-Wind detection of GRB 240926A
  89. GRB 241002B: PRIME near-infrared detection
  90. GRB 241002C: Swift ToO observations
  91. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  92. IPN triangulation of GRB 240930B / EP 240930a
  93. GRB 241001A : SVOM/VT optical detection
  94. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  95. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  96. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  97. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  98. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  99. GRB 241002C : MITSuME Akeno optical upper limits
  100. LIGO/Virgo/KAGRA S240925n: Updated Sky localization

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