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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"

32551 results found.

  1. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  2. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  3. GRB 251122A / EP251122a: LCO optical upper limits
  4. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  5. EP251122a: Global MASTER-Net observations report
  6. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  7. GRB 251122A / EP251122a: SVOM detection of a long burst
  8. EP251118a: Continued Optical Detection with Kinder observations
  9. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  10. LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
  11. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  12. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  13. EP251118a: Xinglong-2.16m optical observation
  14. GRB 251115A: Fermi GBM Observation
  15. EP251118A: 1.3m DFOT optical afterglow detection
  16. GRB 251118A: Swift/UVOT Detection
  17. EP251118a / GRB 251118C: SAO RAS optical observations
  18. GRB 251118A: Glowbug gamma-ray detection
  19. GRB 251118A: Fermi GBM Observation
  20. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  21. EP251118a: Optical detection with Kinder observations
  22. GRB 251118A: GECAM-B detection
  23. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  24. EP251118a / GRB 251118C: SVOM/VT optical observation
  25. GRB 251118A: NuSTAR detection of bright prompt emission
  26. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  27. GRB 251116C: NOT optical observations
  28. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  29. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  30. EP251118A / GRB 251118C : MASTER optical counterpart observations
  31. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  32. Konus-Wind detection of GRB 251118C (EP251118a)
  33. EP251118a: FTW optical and NIR observations
  34. GRB 251117A: Insight-HXMT/HE detection
  35. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  36. EP251118a: VLT near-infrared observation
  37. GRB 251116D: SVOM/GRM observation of a long GRB
  38. EP251118a: GOTO optical afterglow detection
  39. EP251118a: NOT spectroscopic redshift of z = 1.216
  40. EP251118a: Global MASTER-Net observations report
  41. EP251118a: preliminary result of EP-FXT follow-up observation
  42. GRB 251118A: Fermi-LAT detection
  43. EP251118a: NOT candidate optical counterpart
  44. GRB 251118A: Swift ToO observations
  45. EP251118a: Einstein Probe detected of a fast X-ray transient
  46. Fermi GRB 251118B: Global MASTER-Net observations report
  47. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  48. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  49. GRB 251116C: SVOM/ECLAIRs refined analysis
  50. GRB 251116B: SVOM/ECLAIRs refined analysis
  51. GRB 251117A: AstroSat CZTI detection
  52. GRB 251114B: Insight-HXMT/HE detection
  53. GRB 251114B: GECAM-B detection of a short burst
  54. GRB 251117A: Fermi GBM observation
  55. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  56. LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
  57. GRB 251116D: Insight-HXMT/HE detection
  58. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  59. GRB 251117A: SVOM/GRM observation of a short burst
  60. GRB 251117A: Tiled Swift observations
  61. GRB 251117A: Fermi-LAT detection
  62. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  63. GRB 251116C: Swift/BAT arcminute localization of a burst
  64. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  65. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  66. GRB 251116B: SVOM/VT optical upper limit
  67. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  68. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  69. GRB 251116D: Glowbug gamma-ray detection
  70. EP251023a: Assy AZT-20 optical observations
  71. EP251023a: UAFO and AbAO optical observations
  72. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  73. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  74. GRB 251116C: SVOM/VT optical upper limit
  75. GRB 251025B: further Mondy optical observations
  76. GRB 251111A: Mondy optical upper limit
  77. GRB 251116B: EP-FXT follow-up observation
  78. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  79. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  80. GRB 251116B: LCO optical upper limits
  81. GRB 251116C: LCO optical upper limits
  82. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  83. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  84. GRB 251115A: Tiled Swift observations
  85. GRB 251115A: Fermi-LAT detection
  86. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  87. Fermi GRB 251115A: Global MASTER-Net observations report
  88. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  89. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  90. GRB 251113A: Glowbug gamma-ray detection
  91. GRB 251113A: AstroSat CZTI detection
  92. GRB 251112A: Swift-BAT refined analysis
  93. Konus-Wind detection of GRB 251108C
  94. Konus-Wind detection of GRB 251103A
  95. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  96. IPN triangulation of GRB 251108C
  97. Fermi GRB 251114A: Global MASTER-Net observations report
  98. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  99. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  100. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region

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