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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

24458 results found.

  1. GRB 250114B: Swift-XRT observations
  2. GRB 250114B: OHP/T193 optical upper limit
  3. GRB 250114A: Swift-XRT refined Analysis
  4. Integral GRB250114.55: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  6. GRB 250113A: INTEGRAL/SPI-ACS detection
  7. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  8. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  9. Swift GRB250114A: Global MASTER-Net OT detection
  10. GRB 250114A: TRT optical observations
  11. Swift GRB 250114A: Global MASTER-Net observations report
  12. GRB 250114A: Swift detection of a burst with an optical counterpart
  13. GRB 250113A: SVOM/GRM observation of a long burst
  14. GRB 250107A: VZLUSAT-2 detection
  15. EP250109b: optical upper limits with the Liverpool Telescope
  16. GRB 250109A / EP250109a: GRBAlpha detection
  17. GRB 250107D: GRBAlpha detection
  18. GRB 250106A: Swift-XRT afterglow detection
  19. Fermi trigger No 758442826: Global MASTER-Net observations report
  20. EP250111a: KAIT optical observations
  21. GRB 250109A / EP250109a: Mephisto optical upper limits
  22. EP250108a: Mephisto detection
  23. EP250111a: Global MASTER-Net observations report
  24. EP250111a: Swift/XRT detection and fading
  25. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  26. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  27. GRB 250101B: Fermi GBM Observation
  28. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  29. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  30. Konus-Wind detection of GRB 250107C
  31. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  32. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  33. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  34. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  35. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  36. EP250108a: EP-FXT follow-up observation
  37. GRB 250109A: Fermi GBM Observation
  38. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  39. Konus-Wind detection of GRB 250107D (short/hard)
  40. IPN triangulation of GRB 250107D (short/hard)
  41. IPN triangulation of GRB 250107C
  42. GRB 250108B: Gemini-North likely redshift z = 2.197
  43. GRB 250108B: Swift-BAT refined analysis
  44. GRB 250108B: 1.3m DFOT upper limit
  45. GRB 250108B: REM optical/NIR upper limits
  46. GRB 250109A /EP250109a: Fermi GBM Final Localization
  47. EP250109a: SVOM/VT optical candidate
  48. EP250109a: Global MASTER-Net observations report
  49. EP250108a: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  51. GRB 250108A: NOT optical upper limit
  52. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  53. GRB 250108B: Swift-XRT refined Analysis
  54. Swift GRB 250108B: Global MASTER-Net observations report
  55. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  56. GRB 250103A: 1.6m Mephisto optical observations
  57. GRB 250108A: Swift-XRT afterglow detection
  58. GRB 250108A:SVOM/VT optical candidate
  59. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  60. GRB 250103A: Swift-XRT afterglow detection
  61. GRB 250108A: SVOM detection of a soft long burst
  62. GRB 250107A: Fermi GBM Observation
  63. GRB 241228B: Fermi-LAT detection
  64. Fermi GRB 250107B: Global MASTER-Net observations report
  65. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  66. GRB 250107B: Fermi GBM Final Real-time Localization
  67. GRB 250107A: Fermi GBM Final Real-time Localization
  68. EPWXT01709129925: Xinglong optical observations
  69. GRB 250106A: NOT optical observations
  70. LIGO/Virgo/KAGRA S250104v: Updated Sky localization
  71. GRB 250103B: REM optical/NIR upper limits
  72. GRB 250101A: REM optical/NIR counterpart detection
  73. GRB 250106A: SVOM/VT optical candidate
  74. GRB 250106A: SVOM detection of a long burst
  75. Fermi trigger No 757753930: Global MASTER-Net observations report
  76. GRB 241229A: SVOM/VT optical upperlimit
  77. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  78. GRB 250101A: 1.3m DFOT optical afterglow detection
  79. GRB 241229A: 1.3m DFOT upper limit
  80. GRB 241228B: 1.3m DFOT Optical observations
  81. GRB 241228A: 1.3m DFOT upper limit
  82. GRB 250103B：SVOM/VT optical counterpart
  83. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  84. GRB 250103A: Montarrenti Observatory optical detection
  85. GRB 250103A: NOT optical observations
  86. GRB 250103A: Fermi GBM Observation
  87. GRB 250103B: LCOGT Optical Upper Limit
  88. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  89. Swift GRB 250103B: Global MASTER-Net observations report
  90. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  91. GRB 250103B: SVOM detection of a long burst
  92. Fermi GRB 250102A: Global MASTER-Net observations report
  93. GRB 250103A: SVOM/C-GFT optical upper limit
  94. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  95. IceCube Alert 250102.58: Global MASTER-Net observations report
  96. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  97. GRB 250103A: SVOM detection of a long burst
  98. EP250101a: Xinglong optical upper limit
  99. GRB 250102A: Fermi GBM Final Real-time Localization
  100. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO

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