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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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submitter:"Judith Racusin"

28293 results found.

  1. LIGO/Virgo/KAGRA S250818k: MASTER predicovery limits of the AT2025ulz/ZTF25abjmnps KN candidate
  2. LIGO/Virgo/KAGRA S250818k: ENGRAVE observations of SN 2025ulz as a type II supernova
  3. GRB 250823A: Swift-XRT refined Analysis
  4. EP250821a: MeerKAT radio counterpart
  5. GRB 250823A: COLIBRÍ optical observations
  6. GRB 250823A: SVOM/VT optical observation
  7. GRB 250823A: Swift/UVOT Detection
  8. LIGO/Virgo/KAGRA S250818k: COLIBRÍ confirmation of rebrightening of AT2025ulz
  9. GRB 250823A: Fermi GBM Observation
  10. GRB 250823A: Enhanced Swift-XRT position
  11. GRB 250823A: LCOGT Optical Detection
  12. GRB 250823A: Swift detection of a burst
  13. LIGO/Virgo/KAGRA S250818k: HST nIR detection of AT 2025ulz
  14. LIGO/Virgo/KAGRA S250818k: JinShan optical observations of AT2025ulz
  15. LIGO/Virgo/KAGRA S250818k: GTC/OSIRIS Optical Detection of AT2025ulz
  16. LIGO/Virgo/KAGRA S250818k: 3 GHz MeerKAT observations of AT2025ulz
  17. GRB 250806A: Gemini observations of host galaxy candidate
  18. GRB 250821A: Kilonova-Catcher optical upper limits
  19. EP250821a: Swift/XRT counterpart fading
  20. GRB 250821A: Swift-BAT refined analysis
  21. LIGO/Virgo/KAGRA S250818k: Pan-STARRS coverage of the skymap and candidate counterparts
  22. LIGO/Virgo/KAGRA S250818k: NOT optical observations of AT2025ulz
  23. GRB 250821A: VLT/FORS2 Optical Observation
  24. GRB 250821B: SVOM/GRM observation
  25. EP250821a: SVOM/VT optical observation
  26. GRB 250821A: NOT z-band upper limit
  27. GRB 250821A: KAIT optical upper limit
  28. GRB 250821A: Swift-XRT refined Analysis
  29. GRB 250821B: Fermi GBM Detection
  30. GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672)
  31. GRB 250821A: Enhanced Swift-XRT position
  32. GRB 250821A: Swift/UVOT Upper Limits
  33. EP250821a: Rapidly fading optical source detected in Las Cumbres followup
  34. EP250821a: Swift XRT and UVOT counterpart detection
  35. LIGO/Virgo/KAGRA S250818k: GOTO counterpart search and upper limits
  36. EP250821a: Preliminary analysis of the EP-WXT and EP-FXT observations
  37. GRB 250821A: LCOGT Optical Upper Limits
  38. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  39. GRB 250821A: Swift detection of a burst
  40. LIGO/Virgo/KAGRA S250818k: WFST pre-discovery limits and follow-up observations of AT 2025ulz
  41. EP250821a: Einstein Probe detection of an X-ray transient
  42. GRB 250819A: SVOM/GRM observation of a possible “long” duration type I burst
  43. LIGO/Virgo/KAGRA S250818k: WINTER J-band observations of AT 2025ulz
  44. LIGO/Virgo/KAGRA S250818k: ATLAS pre-discovery limits for AT2025ulz
  45. GRB 250814A: Swift/UVOT Upper Limits
  46. GRB 250813B: Swift/UVOT Upper Limit
  47. IPN triangulation of GRB 250816A (short)
  48. IPN triangulation of GRB 250814C (short)
  49. IPN triangulation of GRB 250804B (short)
  50. GRB 250818B: Kilonova-Catcher optical afterglow detection
  51. LIGO/Virgo/KAGRA S250818k: AstroSat CZTI non-detection and upper limits
  52. LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations
  53. LIGO/Virgo/KAGRA S250818k: Updated Sky localization and EM Bright Classification
  54. LIGO/Virgo/KAGRA S250818k: Pan-STARRS pre-detection limits for AT2025ulz
  55. LIGO/Virgo/KAGRA S250818k: Properties of the low-significance GW compact binary merger candidate potentially associated with AT 2025ulz
  56. GRB 250818B: Swift/UVOT Detection
  57. GRB 250818B: optical afterglow detection with Lesedi (GOTO25fzq)
  58. GRB 250818B: SAO RAS optical observations
  59. GRB 250818A: Swift-XRT refined Analysis
  60. GRB 250818B: EP-FXT counterpart detection
  61. GRB 250818A: Swift-BAT refined analysis
  62. GRB 250818B: KAIT optical observations
  63. GRB 250818A: Swift/UVOT Upper Limits
  64. LIGO/Virgo/KAGRA S250818t: Updated Sky localization
  65. GRB 250818A: Enhanced Swift-XRT position
  66. GRB 250813B: SVOM/ECLAIRs refined analysis
  67. GRB 250818A: Fermi GBM Observation
  68. LIGO/Virgo/KAGRA S250818k: Coverage and upper limits from MAXI/GSC observations
  69. GRB 250814A: Further GRAWITA TNG NIR observations
  70. GRB 250818B: Swift-XRT afterglow detection
  71. GRB 250818B: SVOM detection of a short burst
  72. LIGO/Virgo/KAGRA S250818t: Identification of a GW compact binary merger candidate
  73. GRB 250818A: Swift detection of a burst
  74. sb25081602: Swift-XRT observations
  75. GRB 250816A: SVOM/GRM observation of a short burst
  76. GRB 250814A: Swift-BAT refined analysis
  77. GRB 250813B: Liverpool Telescope optical upper limits
  78. GRB 250814A: Further COLIBRÍ optical upper limit
  79. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  80. GRB 250814A: GRAWITA TNG NIR observations
  81. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  82. GRB 250813B: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  83. GRB250814A: TRT optical upper limits
  84. GRB 250814B: SVOM/GRM observation
  85. LIGO/Virgo/KAGRA S250813k: Swift XRT observations, 2 X-ray sources
  86. GRB 250813B: SVOM/GRM observation
  87. GRB 250814A: P200/WIRC observations of the afterglow candidate
  88. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  89. GRB 250814A: KAIT optical upper limit
  90. GRB 250814A: Swift-XRT refined Analysis
  91. GRB 240814A: Fermi GBM Observation
  92. GRB 250814A: Possible afterglow candidate from P200/WIRC
  93. GRB 250813B: Fermi GBM Observation
  94. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  95. GRB 250814A: J-band upper limit from WINTER
  96. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  97. GRB 250813B: NOT observations of the optical afterglow
  98. GRB 250814A: COLIBRÍ optical upper limit
  99. GRB 250813A: AstroSat CZTI detection
  100. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT

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