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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').
Advanced Search

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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32801 results found.

  1. GRB030329: RTT150 optical observations
  2. GRB 030329: Supernova Spectrum Emerging
  3. GRB030329: Kiso B and R band observations
  4. GRB030329: RTT150 optical observation
  5. GRB030329: More AAVSO VR obs
  6. GRB030328: R upper limit after 6 hours by MASTER
  7. GRB 030329: BV photographic observations
  8. GRB 030329: SARA Optical Observations
  9. GRB 030329: SARA Optical Observations
  10. GRB030329, fading resumes
  11. GRB 030329, BVRI photometry
  12. SDSS 0.5m PT observations of GRB030329 (correction)
  13. SDSS 0.5m PT observations of GRB030329
  14. GRB 030329, Optical observations
  15. GRB 030329, nearby galaxies
  16. GRB030329, cessation of fading
  17. GRB030329 Radio 23/43/90 GHz observations at Nobeyama
  18. GRB 030329: Sub-millimeter detection
  19. GRB 030329: SARA Optical Observations
  20. GRB 030329: SARA Optical Observations
  21. OT GRB light curves and SN predictions
  22. GRB030329, optical observation
  23. GRB030329, new UBVRcIc field photometry
  24. GRB 030329, light curve and SN prediction
  25. GRB030329: optical observations at Tokyo Tech
  26. GRB 030329: optical observations
  27. GRB030329: multiple re-brightening phases
  28. GRB 030329, BRI photometry
  29. GRB 030329 , SPM optical observations
  30. GRB 030329: Radio observations at GMRT
  31. Further AAVSO V,B,R observations of GRB030329
  32. GRB 030329: Additional Mt. Laguna Optical Observations
  33. GRB 030329: SARA Optical Observations
  34. GRB 030329: Observations with ANDICAM
  35. GRB030329: further optical photometry and evidence for a light curve discontinuity
  36. GRB 030329: Correction to GCN 2056
  37. GRB 030329: fitting parameters and re-brightening
  38. GRB 030329: KAIT optical photometry
  39. GRB030329 Further RBO Optical Observations
  40. triangulation of GRB 030331 (single error box)
  41. GRB030329 - OT rebrightens
  42. GRB 030329: SARA Optical Observations
  43. AAVSO V & R observations of GRB030329
  44. IPN triangulation of GRB030331 (annulus)
  45. GRB 030329: optical observations
  46. IPN triangulation of GRB030329b (large error box)
  47. GRB 030329: beginning of the new fading phase in optical band
  48. GRB 030329, optical spectroscopy
  49. GRB 030329: fading X-ray afterglow with RXTE
  50. GRB 030329: optical photometry
  51. Photometry of GRB030329 - Constant OT Magnitude
  52. GRB 030329, R-band observations
  53. GRB 030329, R-band light curve
  54. GRB 030329: further optical observations
  55. GRB030329 - OT brightens
  56. GRB 030329: OT observations at Kanazawa
  57. GRB030329 15 GHz radio observation
  58. GRB 030329 RBO V Optical Observations
  59. GRB 030329, optical photometry
  60. GRB030329: Near Infrared Observations
  61. 030331 NOT A GRB
  62. INTEGRAL GRB 030331
  63. GRB 030324: Optical and NIR Observations
  64. GRB 030328, optical photometry
  65. GRB030329: R band light curve by MASTER
  66. GRB030329 - Light curve flattening
  67. GRB 030329: SARA Optical Observations
  68. GRB 030324, optical search
  69. GRB030329 - near contemporaneous optical limits from CONCAM
  70. GRB 030329, optical observations
  71. GRB 030329: Light curve observed during the change of its slope.
  72. GRB030329, BVRcIc field photometry
  73. GRB030329, SPM optical observations
  74. GRB 030329: Optical Decay
  75. Redshift of GRB 030329
  76. GRB030329: ROTSE network observes steepening of decay curve
  77. GRB 030329, optical photometry
  78. GRB 030329: Optical decay and synthesis
  79. GRB 030329: Radio Observations
  80. GRB 030329, optical spectroscopy
  81. GRB 030329: still bright
  82. GRB 030329: Optical pre-Imaging
  83. GRB 030329: visual observations
  84. GRB 030329: Upper limit from 5.6 hours before trigger
  85. GRB030328: R optical observation
  86. GRB 030323: Gemini South VRI obsevations.
  87. GRB030329: Optical observations
  88. GRB 030329, R-band observations, supplement
  89. GRB030329:optical observations by MASTER
  90. GRB 030329: optical observations
  91. GRB 030329, R-band observations
  92. GRB 030329: OT B and R photometry, decline rate
  93. GRB030329: Upper limits from recent and historical observations.
  94. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  95. RXTE detection of GRB 030329 afterglow
  96. GRB 030329: Optical Afterglow Observations
  97. GRB 030329: precise position from Kyoto images
  98. GRB 030328 Optical Observations
  99. GRB 030328: Optical observations
  100. GRB 030328: optical observations

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