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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"

43960 results found.

  1. EP250125a: Optical upper limit with Kinder observations
  2. EP250125a: REM optical counterpart detection
  3. GRB 250119C: Fermi GBM Observation
  4. EP250125a: Swift/XRT detection of a fading counterpart
  5. EP250125a: a new X-ray transient detected by Einstein Probe
  6. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  7. The EP-WXT trigger 01709130758 is a false trigger
  8. The EP-WXT trigger 01709130758 is a false trigger
  9. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  10. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  11. IPN triangulation of a bright burst from SGR 1E1841-045
  12. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  13. EP250108a: AbAO, CMO and Terskol optical upper limits
  14. Konus-Wind detection of GRB 250118B
  15. GRB 250121A: Fermi GBM Observation
  16. IPN triangulation of GRB 250118B
  17. Konus-Wind detection of GRB 250119B
  18. IPN triangulation of GRB 250119B
  19. GRB 250122A: Fermi GBM Final Real-time Localization
  20. Improved IPN triangulation of GRB 250107C
  21. GRB 250114A: Swift-BAT refined analysis
  22. GRB 250121A: INTEGRAL/SPI-ACS detection
  23. GRB 250121A: Fermi-LAT detection
  24. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  25. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  26. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  27. GRB 250121A: Fermi GBM Final Real-time Localization
  28. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  29. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  30. GRB 250119B: Fermi GBM Observation
  31. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  32. Konus-Wind detection of GRB 250117A
  33. IPN triangulation of GRB 250117A (short)
  34. ATCA detection of possible radio counterpart to GRB 250114A
  35. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  36. GRB 250119B: INTEGRAL/SPI-ACS detection
  37. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  38. EP 250108A: Late-time optical observation by LCO
  39. GRB 250117A: SVOM/GRM observation of a short burst
  40. LIGO/Virgo/KAGRA S250105bn: 1 counterpart neutrino candidate event from an IceCube neutrino search
  41. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  42. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  43. GRB 250119C: Fermi GBM Final Real-time Localization
  44. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  45. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  46. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  47. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  49. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  50. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  51. GRB 250117A: GECAM observation of a short burst
  52. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  53. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  54. GRB 250119B: Fermi GBM Final Real-time Localization
  55. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  56. GRB 250119A: Fermi GBM Final Real-time Localization
  57. GRB 250118A: Fermi GBM Final Real-time Localization
  58. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  60. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  62. EP250108a / AT2025kg: VLA radio upper limit
  63. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  64. Konus-Wind detection of GRB 250116A
  65. GRB 250116A: GECAM-B detection of a long burst
  66. GRB 241217A / EP241217B: radio detection with the VLA
  67. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  68. Swift Trigger 1282245 is not a GRB
  69. GRB 250116A: Fermi-LAT detection
  70. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  71. GRB 250114B: Swift-XRT afterglow detection
  72. GRB 250114B: SVOM/VT upper limit
  73. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  74. EP250108a: MeerKAT radio upper limit
  75. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  76. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  77. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  78. Konus-Wind detection of GRB 250113A
  79. IPN triangulation of GRB 250113A
  80. GRB 250114B: Liverpool Telescope optical upper limit
  81. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  82. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  83. GRB 250114B: Swift-XRT observations
  84. GRB 250114A: LCO optical counterpart detection.
  85. GRB 250114B: OHP/T193 optical upper limit
  86. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  87. GRB 250114A: Swift-XRT refined Analysis
  88. Integral GRB250114.55: Global MASTER-Net observations report
  89. GRB 250114A: LCOGT optical afterglow i-band detection
  90. GRB 250114B : GIT optical upper limit
  91. GRB 250114B: Swift ToO observations
  92. EP250111a: SAO RAS optical upper limit
  93. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  94. GRB 250114B: a short GRB detected with INTEGRAL
  95. EP250108a: correction to GCN 38908
  96. GRB 250114A: Enhanced Swift-XRT position
  97. GRB 250113A: INTEGRAL/SPI-ACS detection
  98. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  99. GRB 250114A: REM detection of the optical and NIR counterpart
  100. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate

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