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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"

43952 results found.

  1. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 1)
  2. GRB 250327B: ALMA detection
  3. GRB 250327B: VLA detection
  4. GRB 250329B: SVOM/VT optical upper limit
  5. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  6. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  7. LIGO/Virgo/KAGRA S250329fl: 2 counterpart neutrino candidate events from an IceCube neutrino search
  8. GRB250329A: REM optical afterglow detection
  9. GRB 250329B: GWAC-F50A optical upper limit
  10. GRB 250329B: SVOM detection of a faint transient
  11. GRB 250329A: Swift-XRT afterglow detection
  12. GRB 250328A: SVOM/VT optical observation
  13. GRB 250329A: Fading optical counterpart detection by LCO.
  14. GRB 250328A: SVOM/C-GFT optical upper limit
  15. GRB 250328A: SVOM/COLIBRÍ (F-GFT) optical afterglow candidate
  16. GRB 250328A: VLT/HAWK-I near-infrared afterglow candidate
  17. GRB 250329A: VLT/X-shooter redshift z = 2.921
  18. GRB 250329A: SVOM/VT optical counterpart confirmation
  19. GRB 250329A: SVOM detection of a burst
  20. GRB 250329A: SVOM/COLIBRÍ (F-GFT) Detection of a Bright Optical Counterpart Candidate
  21. GRB 250327B: J-band observations with WINTER
  22. GRB 250327B: MASTER detection of OT rebrightening
  23. GRB 250327B: LCO optical counterpart detection
  24. GRB 250328A: GWAC-F50A optical upper limit
  25. GRB 250328A: SVOM detection of a burst
  26. FRB 20250316A: FTW optical observations
  27. LIGO/Virgo/KAGRA S250328ae: NED Galaxies in the 4-Update Localization Volume
  28. EP250302a: SPI-ACS/INTEGRAL Upper Limit
  29. GRB 250327B: CrAO and SAO RAS Optical Observations
  30. GRB 250327B: OHP/T193 spectroscopic observations and redshift confirmation
  31. GRB 250327B: further optical observations by LCOGT
  32. EP250315a: Pan-STARRS r and i-band imaging and photometry
  33. GRB 250327b: Liverpool Telescope optical observations
  34. GRB 250322A: GRANDMA/TNOT optical upper limits
  35. LIGO/Virgo/KAGRA S250328ae: Updated Sky localization
  36. GRB 250327A: SVOM/VT upper limits on the XRT position
  37. LIGO/Virgo/KAGRA S250328ae: Identification of a GW compact binary merger candidate
  38. GRB 250327B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  39. GRB 250327B: Las Cumbres optical counterpart detection
  40. GRB 250327B: Swift-XRT detection of the X-ray afterglow
  41. GRB 250327B: 1.6m Mephisto optical observations
  42. GRB 250327B: NOT spectroscopic redshift z = 3.035
  43. GRB 250327A: Swift-XRT refined Analysis
  44. GRB 250327B: GOTO optical counterpart detection
  45. GRB 250327B: SVOM/VT optically bright counterpart
  46. GRB 250327B: SAO RAS optical candidate
  47. GRB 250327B: SVOM detection of a burst
  48. FRB 20250316A: Gemini Imaging and Spectroscopy of the Sub-arcsecond Localization Region of FRB 20250316A
  49. FRB 20250316A: The sub-arcsecond localization of FRB 20250316A using CHIME/FRB Outriggers coincides with reported X-ray counterparts
  50. GRB 250327A: J-band observations with WINTER
  51. GRB 250327A: SVOM/VT optical candidate
  52. FRB 20250316A: Pan-STARRS r and i-band imaging and photometry
  53. GRB 250327A: Fermi GBM observation
  54. Fermi GRB 250327A: Global MASTER-Net observations report
  55. Swift GRB 250327A: Global MASTER-Net observations report
  56. GRB 250327A: DDOTI Optical Observations
  57. GRB 250327A: COLIBRÍ optical upper limit
  58. GRB 250327A: Swift detection of a burst
  59. GRB 250327A: Fermi GBM Final Real-time Localization
  60. Fermi trigger No 764700395: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S250326y: Updated Sky localization
  62. Konus-Wind detection of GRB 250322A (short)
  63. IPN triangulation of GRB 250322B
  64. LIGO/Virgo/KAGRA S250326y: Identification of a GW compact binary merger candidate
  65. EP250321a: Mondy AZT-33IK Continued Optical Observations
  66. Swift follow-up observations of FRB250316A and EP J120944.2+585060
  67. GRB 250322A: third epoch of NOT optical observations
  68. GRB 250322A: Swift-BAT refined analysis
  69. The EP-WXT trigger 01709133021 (designated as EP250324a) is not a real source
  70. GRB 250321B: ISON-Kitab RC-36 Optical Upper Limit
  71. FRB 250316A: NOT optical upper limit for the X ray source EP J120944.2+585060
  72. GRB 250322A: further NOT optical observations
  73. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  74. EP250324A: COLIBRÍ/DDRAGO Optical Observations
  75. GRB 250322A: VLT/X-shooter redshift confirmation of the putative host galaxy
  76. FRB 250316A: COLIBRÍ/DDRAGO Optical follow up of the X ray source EP J120944.2+585060
  77. GRB 250322B: NuSTAR detection of the prompt emission and regular dips during the burst
  78. GRB 250321B: Swift-XRT observations
  79. GRB 250322A: Swift-XRT refined Analysis
  80. EP250321a: TNOT Observation of Optical Counterpart
  81. FRB 250316A: DDOTI Continued Optical Observations (Third Epoch)
  82. GRB 250322A: Gemini-North redshift of candidate host galaxy
  83. EP250304a: VLT/MUSE spectroscopic observation of its associated supernova SN 2025fhm
  84. SVOM/sb25032302: SVOM detection of a long X-ray transient
  85. GRB 250322A: AstroSat CZTI detection of a short burst
  86. GRB 250322B: AstroSat CZTI detection of a bright long burst
  87. GRB250322A: STEP/T80S optical limits
  88. GRB 250322A: Gemini-South optical observations
  89. GRB 250322A: VLT optical observations
  90. GRB 250322A: VLT near-infrared observations
  91. FRB 250316A: DDOTI Continued Optical Observations
  92. GRB 250322A: NOT optical upper limits
  93. GRB 250322A: Enhanced Swift-XRT position
  94. GRB 250321B: SVOM/COLIBRÍ (F-GFT) follow-up observations
  95. FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
  96. GRB 250322A: MASTER optical observation
  97. EP250321a: Liverpool Telescope optical follow-up
  98. EP250321a: Mondy AZT-33IK Optical Observations
  99. GRB 250322A: Swift detection of a short burst
  100. FRB 20250316A: detection of a candidate associated X-ray source EP J120944.2+585060 by Einstein Probe

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