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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"

24381 results found.

  1. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  2. GRB 251114B: Fermi GBM Final Real-time Localization
  3. GRB 251112A: Swift-BAT refined analysis
  4. Konus-Wind detection of GRB 251108C
  5. Fermi trigger No 784717756: Global MASTER-Net observations report
  6. Konus-Wind detection of GRB 251103A
  7. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  8. IPN triangulation of GRB 251108C
  9. The EP-WXT trigger 01709248221 is likely a flaring star
  10. Fermi GRB 251114A: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  12. GRB 251114A: Fermi GBM Final Real-time Localization
  13. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  14. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  15. Fermi GRB 251113A: Global MASTER-Net observations report
  16. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  17. GRB 251113A: Fermi GBM Final Real-time Localization
  18. GRB 251111A: SVOM/ECLAIRs refined analysis
  19. GRB 251025B: SVOM/ECLAIRs refined analysis
  20. GRB 251108C: AstroSat CZTI detection
  21. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  22. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  23. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  24. GRB 251108B: Glowbug gamma-ray detection
  25. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  26. Fermi trigger No 784621743: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  28. GRB251111A: 1.3m DFOT optical upper limit
  29. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  30. GRB 251111A: SVOM/VT optical observations with X-band data
  31. SVOM GRB251111.42: Global MASTER-Net observations report
  32. SVOM GRB251111.22: Global MASTER-Net observations report
  33. GRB 251111A: EP-FXT counterpart detection
  34. GRB 251111A: LCO optical observation
  35. GRB 251111A: SVOM detection of a soft burst
  36. GRB 251103B: Swift-BAT refined analysis
  37. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  38. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  39. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  40. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  41. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  42. GRB 251108A: Fermi GBM Final Localization Correction
  43. Fermi trigger No 784329591: Global MASTER-Net observations report
  44. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  45. Fermi trigger No 784279167: Global MASTER-Net observations report
  46. SVOM GRB251108.54: Global MASTER-Net observations report
  47. GRB 251102B: SVOM/GRM observation
  48. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  49. The EP-WXT trigger 01709248051 is likely a flaring star
  50. SVOM GRB251106.83: Global MASTER-Net observations report
  51. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  52. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  53. IPN triangulation of GRB 251105B (possible sGRB with EE)
  54. Fermi GBM Sub-Threshold Detection of GRB 251106A
  55. GRB 251106A: Swift/BAT arcminute localization of a burst
  56. GRB 251106A: MASTER optical observations
  57. GRB 251106A: SVOM detection of a burst
  58. GRB 251103B: AstroSat CZTI detection
  59. Fermi trigger No 784034269: Global MASTER-Net observations report
  60. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  61. GRB 251105A: Fermi GBM Observation
  62. GRB 251105C: Fermi GBM Final Localization Correction
  63. LIGO/Virgo/KAGRA S251031dw: Candidates from the Zwicky Transient Facility
  64. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  65. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  66. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  67. Fermi GBM Sub-Threshold Detection of GRB 251105B
  68. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  69. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  70. Fermi GRB 251105A: Global MASTER-Net observations report
  71. GRB 251105A: Fermi GBM Final Real-time Localization
  72. GRB 251103B: Fermi GBM observation
  73. GRB 251104A: SVOM detection of a burst
  74. EP251102a: update of EP-FXT follow-up observation
  75. GRB 251103A: Xinglong 2.16m optical detection
  76. GRB 251103A: KAIT optical observations
  77. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  78. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  79. GRB 251103B: MITSuME Akeno optical upper limits
  80. GRB 251103B: Swift-XRT refined Analysis
  81. Fermi GRB 251103A: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  83. Swift GRB 251103B: Global MASTER-Net observations report
  84. GRB 251103B: GROWTH-India Telescope optical upper limits
  85. GRB 251103B: Fermi GBM Final Real-time Localization
  86. GRB 251103A: Fermi GBM Observation
  87. GRB 251103A: SVOM/GRM observation
  88. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  89. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  90. GRB 251103A: LCO optical afterglow detection
  91. GRB 251103A: Fermi GBM Final Localization
  92. GRB 251103A: SVOM detection of a bright burst
  93. GRB 251102B: Fermi GBM Final Real-time Localization
  94. Fermi GRB 251102A: Global MASTER-Net observations report
  95. GRB 251102A: Fermi GBM Final Real-time Localization
  96. GRB 251031A: Fermi GBM Observation
  97. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  98. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  99. Konus-Wind detection of GRB 251028A
  100. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)

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