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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.

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

24378 results found.

  1. Konus-Wind detection of GRB 251108C
  2. Fermi trigger No 784717756: Global MASTER-Net observations report
  3. Konus-Wind detection of GRB 251103A
  4. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  5. IPN triangulation of GRB 251108C
  6. The EP-WXT trigger 01709248221 is likely a flaring star
  7. Fermi GRB 251114A: Global MASTER-Net observations report
  8. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  9. GRB 251114A: Fermi GBM Final Real-time Localization
  10. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  11. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  12. Fermi GRB 251113A: Global MASTER-Net observations report
  13. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  14. GRB 251113A: Fermi GBM Final Real-time Localization
  15. GRB 251111A: SVOM/ECLAIRs refined analysis
  16. GRB 251025B: SVOM/ECLAIRs refined analysis
  17. GRB 251108C: AstroSat CZTI detection
  18. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  19. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  20. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  21. GRB 251108B: Glowbug gamma-ray detection
  22. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  23. Fermi trigger No 784621743: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  25. GRB251111A: 1.3m DFOT optical upper limit
  26. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  27. GRB 251111A: SVOM/VT optical observations with X-band data
  28. SVOM GRB251111.42: Global MASTER-Net observations report
  29. SVOM GRB251111.22: Global MASTER-Net observations report
  30. GRB 251111A: EP-FXT counterpart detection
  31. GRB 251111A: LCO optical observation
  32. GRB 251111A: SVOM detection of a soft burst
  33. GRB 251103B: Swift-BAT refined analysis
  34. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  35. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  36. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  37. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  38. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  39. GRB 251108A: Fermi GBM Final Localization Correction
  40. Fermi trigger No 784329591: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  42. Fermi trigger No 784279167: Global MASTER-Net observations report
  43. SVOM GRB251108.54: Global MASTER-Net observations report
  44. GRB 251102B: SVOM/GRM observation
  45. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  46. The EP-WXT trigger 01709248051 is likely a flaring star
  47. SVOM GRB251106.83: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  49. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  50. IPN triangulation of GRB 251105B (possible sGRB with EE)
  51. Fermi GBM Sub-Threshold Detection of GRB 251106A
  52. GRB 251106A: Swift/BAT arcminute localization of a burst
  53. GRB 251106A: MASTER optical observations
  54. GRB 251106A: SVOM detection of a burst
  55. GRB 251103B: AstroSat CZTI detection
  56. Fermi trigger No 784034269: Global MASTER-Net observations report
  57. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  58. GRB 251105A: Fermi GBM Observation
  59. GRB 251105C: Fermi GBM Final Localization Correction
  60. LIGO/Virgo/KAGRA S251031dw: Candidates from the Zwicky Transient Facility
  61. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  62. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  63. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  64. Fermi GBM Sub-Threshold Detection of GRB 251105B
  65. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  66. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  67. Fermi GRB 251105A: Global MASTER-Net observations report
  68. GRB 251105A: Fermi GBM Final Real-time Localization
  69. GRB 251103B: Fermi GBM observation
  70. GRB 251104A: SVOM detection of a burst
  71. EP251102a: update of EP-FXT follow-up observation
  72. GRB 251103A: Xinglong 2.16m optical detection
  73. GRB 251103A: KAIT optical observations
  74. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  75. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  76. GRB 251103B: MITSuME Akeno optical upper limits
  77. GRB 251103B: Swift-XRT refined Analysis
  78. Fermi GRB 251103A: Global MASTER-Net observations report
  79. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  80. Swift GRB 251103B: Global MASTER-Net observations report
  81. GRB 251103B: GROWTH-India Telescope optical upper limits
  82. GRB 251103B: Fermi GBM Final Real-time Localization
  83. GRB 251103A: Fermi GBM Observation
  84. GRB 251103A: SVOM/GRM observation
  85. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  86. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  87. GRB 251103A: LCO optical afterglow detection
  88. GRB 251103A: Fermi GBM Final Localization
  89. GRB 251103A: SVOM detection of a bright burst
  90. GRB 251102B: Fermi GBM Final Real-time Localization
  91. Fermi GRB 251102A: Global MASTER-Net observations report
  92. GRB 251102A: Fermi GBM Final Real-time Localization
  93. GRB 251031A: Fermi GBM Observation
  94. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  95. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  96. Konus-Wind detection of GRB 251028A
  97. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  98. GRB 251031A: Fermi GBM Final Real-time Localization
  99. GRB 251025C: SVOM/GRM observation
  100. GRB 251028A: GECAM-B detection

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