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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"

32756 results found.

  1. Swift GRB 250821A: Global MASTER-Net observations report
  2. LIGO/Virgo/KAGRA S250818k: ENGRAVE observations of AT 2025ulz
  3. LIGO/Virgo/KAGRA S250818k : Tautenburg observations, upper limits
  4. GRB 250821A: Swift/UVOT Upper Limits
  5. EP250821a: Rapidly fading optical source detected in Las Cumbres followup
  6. EP250821a: Swift XRT and UVOT counterpart detection
  7. LIGO/Virgo/KAGRA S250818k: GOTO counterpart search and upper limits
  8. EP250821a: Preliminary analysis of the EP-WXT and EP-FXT observations
  9. GRB 250821A: LCOGT Optical Upper Limits
  10. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  11. LIGO/Virgo/KAGRA S250818k: 10 GHz VLA observations of AT2025ulz
  12. LIGO/Virgo/KAGRA S250818k: WFST pre-discovery limits and follow-up observations of AT 2025ulz
  13. LIGO/Virgo/KAGRA S250818k: EP/FXT observation of AT 2025ulz
  14. GRB 250819A: SVOM/GRM observation of a possible “long” duration type I burst
  15. LIGO/Virgo/KAGRA S250818k: WINTER J-band observations of AT 2025ulz
  16. GRB 250818B: 10 GHz VLA detection
  17. LIGO/Virgo/KAGRA S250818k: Pan-STARRS grizy-band imaging and photometry of AT2025ulz
  18. LIGO/Virgo/KAGRA S250818k: Swift observations of AT 2025ulz
  19. LIGO/Virgo/KAGRA S250818k: Multi-band Gemini GMOS Detections
  20. LIGO/Virgo/KAGRA S250818k: ATLAS pre-discovery limits for AT2025ulz
  21. GRB 250814A: Swift/UVOT Upper Limits
  22. GRB 250813B: Swift/UVOT Upper Limit
  23. IPN triangulation of GRB 250816A (short)
  24. IPN triangulation of GRB 250814C (short)
  25. IPN triangulation of GRB 250804B (short)
  26. GRB 250818B: FTW optical and NIR observations show reddening of the counterpart
  27. GRB 250818B: Kilonova-Catcher optical afterglow detection
  28. LIGO/Virgo/KAGRA S250818k: AstroSat CZTI non-detection and upper limits
  29. GRB 250818B: Liverpool Telescope optical detections
  30. LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations
  31. LIGO/Virgo/KAGRA S250818k: Updated Sky localization and EM Bright Classification
  32. LIGO/Virgo/KAGRA S250818k: Pan-STARRS pre-detection limits for AT2025ulz
  33. GRB 250818A: AstroSat CZTI detection
  34. LIGO/Virgo/KAGRA S250818k: Properties of the low-significance GW compact binary merger candidate potentially associated with AT 2025ulz
  35. LIGO/Virgo/KAGRA S250818k: Keck I LRIS spectroscopy of ZTF25abjmnps (AT2025ulz)
  36. GRB 250818B: Swift/UVOT Detection
  37. LIGO/Virgo/KAGRA S250818k: FTW Fast reddening of AT 2025ulz
  38. GRB 250818B: optical afterglow detection with Lesedi (GOTO25fzq)
  39. GRB 250818B: TRT Optical Observation
  40. Fermi GRB 250816A: Global MASTER-Net observations report
  41. GRB 250818B: SAO RAS optical observations
  42. Swift GRB 250818A: Global MASTER-Net observations report
  43. GRB 250818B: NOT optical observations
  44. GRB 250818B: EP-FXT counterpart detection
  45. GRB 250818A: Swift-BAT refined analysis
  46. LIGO/Virgo/KAGRA S250818k: FTW optical and NIR observations of AT 2025ulz
  47. GRB 250818B: Keck redshift of the optical afterglow
  48. GRB 250818B: KAIT optical observations
  49. GRB 250818A: Swift/UVOT Upper Limits
  50. LIGO/Virgo/KAGRA S250818t: Updated Sky localization
  51. GRB 250813B: SVOM/ECLAIRs refined analysis
  52. GRB 250818A: Fermi GBM Observation
  53. GRB 250818B: SVOM/VT optical observation
  54. GRB 250814A: Further GRAWITA TNG NIR observations
  55. GRB 250818B: Swift-XRT afterglow detection
  56. GRB 250818B: GOTO optical counterpart candidate
  57. GRB 250818B: SVOM detection of a short burst
  58. LIGO/Virgo/KAGRA S250818t: Identification of a GW compact binary merger candidate
  59. sb25081602: Swift-XRT observations
  60. GRB 250816A: SVOM/GRM observation of a short burst
  61. Fermi GRB 250814B: Global MASTER-Net observations report
  62. GRB 250814A: Swift-BAT refined analysis
  63. GRB 250813B: Liverpool Telescope optical upper limits
  64. GRB 250814A: Further COLIBRÍ optical upper limit
  65. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  66. GRB 250814A: GRAWITA TNG NIR observations
  67. GRB 250812A: SVOM/VT optical continued observation
  68. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  69. GRB 250813B: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  70. GRB250814A: TRT optical upper limits
  71. GRB 250814B: SVOM/GRM observation
  72. GRB 250813B: SVOM/GRM observation
  73. GRB 250814A: P200/WIRC observations of the afterglow candidate
  74. GRB 250814A: KAIT optical upper limit
  75. GRB 240814A: Fermi GBM Observation
  76. GRB 250814A: Possible afterglow candidate from P200/WIRC
  77. GRB 250813B: Fermi GBM Observation
  78. GRB 250814A: J-band upper limit from WINTER
  79. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 250813B: NOT observations of the optical afterglow
  81. GRB 250813B: SVOM/VT optical observations
  82. Subject GRB 250813B: SVOM/MXT refined analysis
  83. GRB 250814A: COLIBRÍ optical upper limit
  84. GRB 250813A: AstroSat CZTI detection
  85. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  86. GRB 250813B: VLT X-shooter spectroscopic redshift z = 1.752
  87. GRB 250814A: DDOTI Optical Upper Limit
  88. GRB 250813B: EP-FXT counterpart detection
  89. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  90. GRB 250813B: Swift-XRT afterglow detection
  91. GRB 250813B: SVOM/COLIBRÍ (FM-GFT) optical observations
  92. GRB 250813B: Ondrejov D50 fast decay
  93. GRB 250813B: SVOM detection of a bright long burst (Correction for GCN 41352).
  94. GRB 250813B: Ondrejov D50 optical afterglow detection
  95. LIGO/Virgo/KAGRA S250813k: Updated Sky localization
  96. EP250812a: Nickel optical upper limit
  97. GRB 250812A: VLT X-shooter spectroscopic redshift confirmation z = 2.571
  98. GRB 250812A: NTT spectroscopic redshift z = 2.57
  99. GRB250812a: STEP/T80S Indication of slow decay of afterglow
  100. EP250812a: NOT, NTT, and GS observations

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