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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"

20518 results found.

  1. GRB 250128B: GOTO optical upper limit
  2. GRB 250128B: LCO optical observations
  3. GRB 250128B: Swift detection of a short burst
  4. GRB 250127A: Swift-XRT observations
  5. GRB 250127B: DDOTI Upper Limit on the Afterglow
  6. IPN triangulation of GRB 250119C
  7. GRB 250127A: LCO optical upper limit
  8. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  9. EP250125a: Optical upper limit with Kinder observations
  10. EP250125a: REM optical counterpart detection
  11. EP250125a: a new X-ray transient detected by Einstein Probe
  12. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  13. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  14. EP250108a: AbAO, CMO and Terskol optical upper limits
  15. IPN triangulation of GRB 250118B
  16. Konus-Wind detection of GRB 250119B
  17. IPN triangulation of GRB 250119B
  18. GRB 250121A: INTEGRAL/SPI-ACS detection
  19. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  20. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  21. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  22. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  23. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  24. GRB 250119B: Fermi GBM Observation
  25. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  26. IPN triangulation of GRB 250117A (short)
  27. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  28. EP 250108A: Late-time optical observation by LCO
  29. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  30. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  31. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  32. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  33. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  34. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  37. EP250108a / AT2025kg: GMG Optical Observations
  38. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  39. Konus-Wind detection of GRB 250116A
  40. GRB 241217A / EP241217B: radio detection with the VLA
  41. GRB 250114B: Swift-XRT afterglow detection
  42. EP250108a: MeerKAT radio upper limit
  43. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  44. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  45. IPN triangulation of GRB 250113A
  46. GRB 250114B: Liverpool Telescope optical upper limit
  47. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  48. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  49. GRB 250114A: LCO optical counterpart detection.
  50. GRB 250114B: OHP/T193 optical upper limit
  51. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  52. GRB 250114A: LCOGT optical afterglow i-band detection
  53. GRB 250114B : GIT optical upper limit
  54. EP250111a: SAO RAS optical upper limit
  55. GRB 250114A: Enhanced Swift-XRT position
  56. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  57. GRB 250114A: REM detection of the optical and NIR counterpart
  58. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  59. GRB 250114A: LCO optical observations
  60. GRB 250114A: TRT optical observations
  61. GRB 250114A: Swift detection of a burst with an optical counterpart
  62. GRB 250101A: Terskol Zeiss-2000 optical observations
  63. EP250108a / AT 2025kg: SAO RAS optical observations
  64. EP241021a: SMA radio observation
  65. GRB 250113A: SVOM/GRM observation of a long burst
  66. EP250109b: optical upper limits with the Liverpool Telescope
  67. GRB 250106A: Swift-XRT afterglow detection
  68. EP250111a: KAIT optical observations
  69. GRB 250109A / EP250109a: Mephisto optical upper limits
  70. EP250108a: Mephisto detection
  71. EP250111a: Mondy optical observation
  72. EP250108a / AT 2025kg: LCO optical observations
  73. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  74. EP250111a: NOT likely optical counterpart
  75. EP250111a: a new X-ray transient detected by Einstein Probe
  76. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  77. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  78. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  79. Konus-Wind detection of GRB 250107C
  80. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  81. GRB 250101A: CMO RC-500 optical observations
  82. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  83. EP250108a: NOT optical observations
  84. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  85. GRB 250109a: GMG Optical Upper Limit
  86. EP250109a: Swift/UVOT non-detection
  87. IPN triangulation of GRB 250107D (short/hard)
  88. EP250108a: Liverpool Telescope likely optical counterpart
  89. GRB 250108B: 1.3m DFOT upper limit
  90. GRB 250108B: REM optical/NIR upper limits
  91. GRB 250107C: SVOM/GRM observation
  92. GRB 250101A: Terskol K-800 optical observations
  93. EP250109a: Swift/XRT non-detection
  94. GRB 250108A: Swift/UVOT Upper Limits
  95. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  96. GRB 250108A: NOT optical upper limit
  97. EP250108a: EP-WXT detection of an X-ray transient
  98. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  99. GRB 250103A: 1.6m Mephisto optical observations
  100. GRB 250108A: Swift-XRT afterglow detection

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