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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

44399 results found.

  1. GRB 241018A: 1.3m DFOT Optical upper limit
  2. GRB 241018A: EP-FXT afterglow detection
  3. EP241021a: GOTO optical upper limits
  4. EP241021a: EP detection of a fast X-ray transient
  5. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  6. Konus-Wind detection of GRB 241018A
  7. GRB 241018A: SVOM/GRM observation
  8. GRB 241018A/sb24101802: Mephisto optical upper limit
  9. GRB 241017A/sb24101702: Mephisto optical upper limit
  10. GRB 241018A: BOOTES-4/MET optical upper limit
  11. GRB 241018A: Mondy optical upper limit
  12. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  13. GRB 241018A: GROWTH-India telescope optical upper limit
  14. GRB241018A: XingLong Optical Upper Limit
  15. GRB 241018A: Swift-XRT observations
  16. GRB 241018A: REM optical/NIR upper limits
  17. GRB 241018A: NOT optical observations
  18. GRB 241017A: SVOM/VT follow-up and optical upper limit
  19. GRB 241018A: SVOM/VT follow-up and optical candidate
  20. GRB 241018A: LCO/0.4m optical upper limits
  21. GRB 241018A: Swift ToO observations
  22. GRB 241006A: VIRT Optical Upper Limit
  23. GRB 240727A: VIRT Optical Upper Limit
  24. GRB 241018A: X-ray afterglow candidate observed by MXT
  25. GRB 241016B: Fermi GBM Observations
  26. GRB 241018A: Detection of a bright long GRB by SVOM
  27. GRB 241017A: Swift-XRT observations
  28. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  29. GRB 241001A: EP-FXT afterglow detection
  30. GRB 241017A: GROWTH-India Telescope optical upper limit
  31. GRB241017A: TOO Observations by SVOM/MXT
  32. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  33. GRB 241017A: J-band upper limit from WINTER
  34. Fermi trigger No 750788395: Global MASTER-Net observations report
  35. GRB 241016B: SVOM/GRM observation
  36. GRB241016C: Fermi GBM Final Localization
  37. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  38. GRB 241017A: Swift ToO observations
  39. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  40. Fermi GRB 241016B: Global MASTER-Net observations report
  41. GRB 241016B: Fermi GBM Final Localization
  42. Fermi GRB 241016A: Global MASTER-Net observations report
  43. GRB 241016A: Fermi GBM Final Real-time Localization
  44. IceCube alert 139977_2910365 retraction
  45. IceCube Alert 241016.04: Global MASTER-Net observations report
  46. GRB 241010A: Swift-BAT refined analysis
  47. GRB 241013B: Fermi GBM Observation
  48. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  49. GRB 241013A: Fermi GBM Observation
  50. GRB 240916A: radio detection with the VLA
  51. GRB241013A: REM observations
  52. GRB 241009A: LCO optical upper limits
  53. GRB 241013B: SVOM/GRM observation
  54. Fermi GRB 241013B: Global MASTER-Net observations report
  55. Integral GRB241013.04: Global MASTER-Net observations report
  56. GRB 241013B: Fermi GBM Final Real-time Localization
  57. GRB 241013A: a long GRB detected by INTEGRAL
  58. GRB 241013A: Fermi GBM Final Real-time Localization
  59. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  60. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  61. LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume
  62. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  63. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  64. GRB 241011A: Fermi GBM Final Real-time Localization
  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 241006A: ATCA Radio Upper Limits
  69. GRB 241010A: Swift-XRT refined Analysis
  70. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  71. Fermi trigger No 750211959: Global MASTER-Net observations report
  72. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  73. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  74. Swift GRB 241010A: Global MASTER-Net observations report
  75. Fermi trigger No 750291012: Global MASTER-Net observations report
  76. GRB 241010A: J-band observations with WINTER
  77. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  78. Fermi GRB 241010B: Global MASTER-Net observations report
  79. GRB 241010B: Fermi GBM Final Real-time Localization
  80. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  81. GRB 241010A: Enhanced Swift-XRT position
  82. GRB 241010A: LCO optical observations
  83. GRB 241010A: Swift detection of a burst with an optical counterpart
  84. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  85. GRB 241006A: Swift-BAT refined analysis
  86. GRB 241009A: Swift ToO observations
  87. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  88. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  89. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  90. GRB 241008A: Fermi GBM Observation
  91. GRB 241008A: Fermi-LAT detection
  92. GRB 241002B: Swift-XRT afterglow detection
  93. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  94. GRB 241002A: NOT optical upper limits
  95. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  96. Fermi GRB 241008A: Global MASTER-Net observations report
  97. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  98. GRB 241008A: Fermi GBM Final Real-time Localization
  99. IceCube-241006A: No candidates from the Zwicky Transient Facility
  100. GRB 241006A: GRANDMA optical upper limits

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