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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"

26507 results found.

  1. EP251118A: 1.3m DFOT optical afterglow detection
  2. GRB 251118A: Swift/UVOT Detection
  3. EP251118a / GRB 251118C: SAO RAS optical observations
  4. GRB 251118A: Glowbug gamma-ray detection
  5. GRB 251118A: Fermi GBM Observation
  6. GRB 251118A: Swift-XRT afterglow detection
  7. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  8. EP251118a: Optical detection with Kinder observations
  9. GRB 251118A: GECAM-B detection
  10. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  11. The EP-WXT trigger 01709248403 is likely a flaring star
  12. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  13. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  14. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  15. GRB 251117A: Swift-XRT observations
  16. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  17. Konus-Wind detection of GRB 251118C (EP251118a)
  18. The EP-WXT trigger 01709248388 is likely a flaring star
  19. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  20. EP251118a: VLT near-infrared observation
  21. GRB 251116D: SVOM/GRM observation of a long GRB
  22. GRB 251119A: SVOM detection of a possible burst
  23. EP251118a: NOT spectroscopic redshift of z = 1.216
  24. EP251118a: NOT candidate optical counterpart
  25. EP251118a: Einstein Probe detected of a fast X-ray transient
  26. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  27. GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
  28. GRB 251116C: SVOM/ECLAIRs refined analysis
  29. GRB 251116B: SVOM/ECLAIRs refined analysis
  30. GRB 251114B: Insight-HXMT/HE detection
  31. GRB 251114B: GECAM-B detection of a short burst
  32. GRB 251117A: Fermi GBM observation
  33. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  34. GRB 251115A: Swift-XRT observations
  35. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  36. GRB 251117A: SVOM/GRM observation of a short burst
  37. GRB 251117A: Fermi-LAT detection
  38. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  39. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  40. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  41. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  42. GRB 251116C: Swift-XRT observations
  43. GRB 251116D: Glowbug gamma-ray detection
  44. EP251023a: Assy AZT-20 optical observations
  45. EP251023a: UAFO and AbAO optical observations
  46. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  47. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  48. GRB 251116C: SVOM/VT optical upper limit
  49. GRB 251025B: further Mondy optical observations
  50. GRB 251111A: Mondy optical upper limit
  51. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  53. GRB 251116B: LCO optical upper limits
  54. GRB 251116C: LCO optical upper limits
  55. GRB 251116C: SVOM detection of a burst
  56. GRB 251116B: SVOM detection of a burst
  57. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  58. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  59. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  60. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  61. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  62. GRB 251113A: Glowbug gamma-ray detection
  63. GRB 251113A: AstroSat CZTI detection
  64. Konus-Wind detection of GRB 251108C
  65. Konus-Wind detection of GRB 251103A
  66. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  67. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  68. The EP-WXT trigger 01709248221 is likely a flaring star
  69. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  70. GRB 251111A: SVOM/ECLAIRs refined analysis
  71. GRB 251025B: SVOM/ECLAIRs refined analysis
  72. GRB 251112A: Swift/UVOT Upper Limits
  73. GRB 251112A: Swift-XRT refined Analysis
  74. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  75. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  76. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  77. GRB 251108B: Glowbug gamma-ray detection
  78. Swift Trigger 1413695: a possible GRB 251112A
  79. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  80. GRB251111A: 1.3m DFOT optical upper limit
  81. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  82. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  83. GRB 251111A: Swift-XRT afterglow detection
  84. GRB 251111A: SVOM/VT optical observations with X-band data
  85. GRB 251111A: Swift-XRT observations
  86. GRB 251013C: Chandra X-ray observations and jet break detection
  87. GRB 251111A: SVOM/VT optical observations with VHF data
  88. GRB 251111A: LCO optical observation
  89. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  90. GRB 251111A: SVOM detection of a soft burst
  91. GRB 251106A: Swift/UVOT Upper Limits
  92. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  93. GRB 251105A: AstroSat CZTI detection
  94. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  95. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  96. GRB 251108A: Fermi GBM Final Localization Correction
  97. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  98. GRB 251102B: SVOM/GRM observation
  99. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  100. The EP-WXT trigger 01709248051 is likely a flaring star

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