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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"

24643 results found.

  1. GRB 241025A: Swift-XRT refined Analysis
  2. GRB 241025C: Fermi GBM Detection
  3. GRB 241025A: Fermi GBM Observation
  4. IPN triangulation of GRB 241022A (short/hard)
  5. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  6. EP 241021a: Swift-XRT observations
  7. GRB 241025A : SVOM/VT optical afterglow observations
  8. EP241021a: Liverpool Telescope optical follow-up observations
  9. GRB 241025A: Enhanced Swift-XRT position
  10. GRB 241025A: DDOTI Afterglow detection
  11. GRB 241025A: TRT optical afterglow observation
  12. GRB 241025A: Swift detection of a burst with an optical counterpart
  13. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  14. GRB 241001A: ATCA radio observations
  15. GRB 241010A: VIRT Optical Upper Limit
  16. EP241021a: SAO RAS optical observations
  17. EP241021a: KAIT optical observations
  18. EP241021a: 1.3m DFOT Optical observations
  19. EP241021a: GSP detects optical candidate counterpart
  20. EP241021a: Optical upper limits with Kinder observations
  21. EP241021a: TRT optical observations
  22. GRB 241018A: SVOM/C-GFT optical observations
  23. EP241021a: NOT likely optical counterpart
  24. EP EP241021a: Global MASTER-Net observations report
  25. GRB241017A: 1.3m DFOT optical upper limit
  26. GRB 241018A: 1.3m DFOT Optical upper limit
  27. EP241021a: GOTO optical upper limits
  28. EP241021a: EP detection of a fast X-ray transient
  29. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 241018A/sb24101802: Mephisto optical upper limit
  31. GRB 241017A/sb24101702: Mephisto optical upper limit
  32. GRB 241018A: Mondy optical upper limit
  33. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  34. GRB 241018A: GROWTH-India telescope optical upper limit
  35. GRB241018A: XingLong Optical Upper Limit
  36. GRB 241018A: Swift-XRT observations
  37. GRB 241018A: REM optical/NIR upper limits
  38. GRB 241018A: NOT optical observations
  39. GRB 241018A: SVOM/VT follow-up and optical candidate
  40. GRB 241018A: LCO/0.4m optical upper limits
  41. GRB 241006A: VIRT Optical Upper Limit
  42. GRB 240727A: VIRT Optical Upper Limit
  43. GRB 241018A: X-ray afterglow candidate observed by MXT
  44. GRB 241017A: Swift-XRT observations
  45. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  46. GRB 241001A: EP-FXT afterglow detection
  47. GRB 241017A: GROWTH-India Telescope optical upper limit
  48. GRB241017A: TOO Observations by SVOM/MXT
  49. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  50. GRB 241017A: J-band upper limit from WINTER
  51. GRB 241016B: SVOM/GRM observation
  52. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  53. GRB 241010A: Swift-BAT refined analysis
  54. GRB 241013B: Fermi GBM Observation
  55. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  56. GRB 241013A: Fermi GBM Observation
  57. GRB 240916A: radio detection with the VLA
  58. GRB241013A: REM observations
  59. GRB 241009A: LCO optical upper limits
  60. Integral GRB241013.04: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  62. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  63. LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume
  64. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  65. GRB 241009A: GRANDMA optical upper limits
  66. GRB 241009A: Swift-XRT afterglow detection
  67. GRB 241010A: JinShan optical observations and potential host galaxy
  68. GRB 241010A: Swift-XRT refined Analysis
  69. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  70. Fermi trigger No 750211959: Global MASTER-Net observations report
  71. Fermi trigger No 750291012: Global MASTER-Net observations report
  72. GRB 241010A: J-band observations with WINTER
  73. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  74. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  75. GRB 241010A: Enhanced Swift-XRT position
  76. GRB 241010A: LCO optical observations
  77. GRB 241010A: Swift detection of a burst with an optical counterpart
  78. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  79. GRB 241006A: Swift-BAT refined analysis
  80. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  81. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  82. GRB 241008A: Fermi GBM Observation
  83. GRB 241002B: Swift-XRT afterglow detection
  84. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  85. GRB 241002A: NOT optical upper limits
  86. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  87. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  88. IceCube-241006A: No candidates from the Zwicky Transient Facility
  89. GRB 241006A: GRANDMA optical upper limits
  90. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  91. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  92. GRB 240910A: LBT optical observations
  93. GRB 241006A: Swift-XRT refined Analysis
  94. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  95. GRB 241006A: PRIME near-infrared upper limits
  96. GRB 241006A: Swift/UVOT Upper Limits
  97. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  98. GRB 241001A: Swift-XRT afterglow detection
  99. GRB 241006A: Enhanced Swift-XRT position
  100. GRB 241006A: Swift detection of a burst

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