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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').
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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"

28274 results found.

  1. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  3. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  4. GRB 251116C: Swift-XRT observations
  5. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  6. GRB 251116D: Glowbug gamma-ray detection
  7. EP251023a: Assy AZT-20 optical observations
  8. EP251023a: UAFO and AbAO optical observations
  9. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  10. GRB 251116C: SVOM/VT optical upper limit
  11. GRB 251025B: further Mondy optical observations
  12. GRB 251111A: Mondy optical upper limit
  13. GRB 251116B: EP-FXT follow-up observation
  14. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  16. GRB 251116B: LCO optical upper limits
  17. GRB 251116C: LCO optical upper limits
  18. SVOM GRB251116C: Global MASTER-Net observations report
  19. GRB 251116B: SVOM detection of a burst
  20. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  21. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  22. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  23. Fermi GRB 251115A: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
  25. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  26. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  27. GRB 251113A: Glowbug gamma-ray detection
  28. GRB 251112A: Swift-BAT refined analysis
  29. Fermi trigger No 784717756: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  31. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  32. Fermi GRB 251114A: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  34. Fermi GRB 251113A: Global MASTER-Net observations report
  35. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  36. GRB 251112A: Swift/UVOT Upper Limits
  37. LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
  38. GRB 251112A: Swift-XRT refined Analysis
  39. GRB 251112B: MAXI/GSC detection
  40. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  41. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  42. GRB 251108B: Glowbug gamma-ray detection
  43. Swift Trigger 1413695: a possible GRB 251112A
  44. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  45. Fermi trigger No 784621743: Global MASTER-Net observations report
  46. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  47. GRB251111A: 1.3m DFOT optical upper limit
  48. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  49. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  50. GRB 251111A: Swift-XRT afterglow detection
  51. GRB 251111A: SVOM/VT optical observations with X-band data
  52. SVOM GRB251111.42: Global MASTER-Net observations report
  53. GRB 251111A: Swift-XRT observations
  54. SVOM GRB251111.22: Global MASTER-Net observations report
  55. GRB 251111A: EP-FXT counterpart detection
  56. GRB 251013C: Chandra X-ray observations and jet break detection
  57. GRB 251111A: SVOM/VT optical observations with VHF data
  58. GRB 251111A: LCO optical observation
  59. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  60. GRB 251103B: Swift-BAT refined analysis
  61. GRB 251106A: Swift/UVOT Upper Limits
  62. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  63. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  64. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  65. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  66. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  67. Fermi trigger No 784329591: Global MASTER-Net observations report
  68. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  69. Fermi trigger No 784279167: Global MASTER-Net observations report
  70. SVOM GRB251108.54: Global MASTER-Net observations report
  71. GRB 251102B: SVOM/GRM observation
  72. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  73. SVOM GRB251106.83: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  75. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  76. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  77. GRB 251106A: Swift-XRT afterglow detection
  78. GRB 251106A: Kilonova-Catcher optical upper limit
  79. Fermi GBM Sub-Threshold Detection of GRB 251106A
  80. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  81. GRB 251106A: MASTER optical observations
  82. GRB 251025C: TERI Gamma-ray detection
  83. GRB 251016B: TERI Gamma-ray detection
  84. GRB 251016A: TERI Gamma-ray detection of a short burst
  85. GRB 250920C: TERI Gamma-ray detection
  86. Fermi trigger No 784034269: Global MASTER-Net observations report
  87. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  88. GRB 251105A: Fermi GBM Observation
  89. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  90. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  91. Fermi GBM Sub-Threshold Detection of GRB 251105B
  92. GRB 251103B: Swift/UVOT Upper Limits
  93. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  94. GRB 251103B: Fermi GBM observation
  95. GRB 251103A: WFST optical observations
  96. GRB 251103A: OHP/T193 optical observations
  97. GRB 251103A: Xinglong 2.16m optical detection
  98. GRB 251103A: KAIT optical observations
  99. GRB 251103B: Nanshan/HMT optical upper limit
  100. GRB 251013C: 7DT detection and Medium-band SED of Afterglow

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