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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"

7408 results found.

  1. XRF040916, Ic observations
  2. XRF040916: optical follow-up observations
  3. GRB040916: Archival optical observations
  4. GRB040916: Optical observations
  5. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  6. GRB 040912, BVRI observations
  7. HETE 3557: Optical observations
  8. GRB 040827 - Radio Observations
  9. GRB040825A: Optical observations
  10. GRB040825A: Optical observations
  11. GRB 040825: Optical observations
  12. XRF040812: possible afterglow second Chandra observation
  13. GRB 040812: Second epoch CXO Observations
  14. XRF040701: Second-Epoch Chandra Observations
  15. XRF 040701, optical observations
  16. GRB 040511, very fast decay?
  17. GRB 030324: Detection and Color of Host Galaxy
  18. GRB040511: Redshift identifcation
  19. GRB 040511: Optical limit
  20. GRB040511: Candidate optical/NIR afterglow
  21. GRB 040403: Optical Observations
  22. MASTER: RXTE GRB040308 optical observation
  23. RXTE GRB040229 optical observation: no candidate
  24. GRB 040228 Optical observations
  25. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  26. GRB040106: Second Epoch Optical Observations
  27. GRB 031220: Optical observations of Chandra X-ray sources
  28. GRB031220 : Optical Observation of Lulin Observatory
  29. GRB 031111: Optical observations
  30. GRB030913: Subaru Optical Observations
  31. GRB030913, candidate afterglow observations
  32. GRB 030913, optical candidate
  33. GRB 030824: Candidate Follow-Up
  34. XRF030824: optical observations
  35. XRF030824: Palomar observations
  36. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  37. RAPTOR observations of GRB030823
  38. GRB 021206 Optical Observations
  39. GRB030725: Optical observations
  40. XRF030723: Re-analysis of ROTSE-III early images
  41. GRB030725, optical transient observations
  42. XRF 030723: VLT spectra
  43. RXTE PCA Observations of SGR1806-20 Region
  44. GRB 021206, Radio afterglow candidate
  45. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  46. GRB 030519B: optical observations.
  47. GRB 030528: Optical observations at RIKEN
  48. GRB030324: Further Observations of the Candidate Optical Afterglow
  49. GRB 030429: IR photometry with IRSF/SIRIUS
  50. GRB030501: TAROT candidate afterglow present in archival images
  51. GRB 030501: TAROT possible candidate counterpart
  52. GRB 030429: confirmation of afterglow candidate
  53. GRB030429, possible optical counterpart
  54. GRB 030429: ROTSE-III observations
  55. GRB 030418: Optical afterglow
  56. GRB 030418: Finder for afterglow candidate
  57. GRB 030418: Optical afterglow candidate
  58. GRB030329, UBVRI polarimetry, R-polarization
  59. GRB030324: Candidate Optical Afterglow (Erratum)
  60. GRB030324: Candidate Optical Afterglow
  61. GRB030329, new UBVRcIc field photometry
  62. GRB 030329: Additional Mt. Laguna Optical Observations
  63. GRB 030329: optical observations
  64. GRB 030329: precise position from Kyoto images
  65. GRB 030329: Optical afterglow fading
  66. GRB 030329: Optical afterglow candidate
  67. GRB 030329: OT candidate
  68. GRB 030329: Optical afterglow candidate
  69. GRB 030328: Finding chart
  70. GRB 030328: Optical afterglow candidate
  71. GRB030324 optical observation
  72. GRB030131, BVRcIc field photometry
  73. GRB030324, optical observations
  74. GRB030324, optical observations
  75. GRB030323: V, R, I photometry
  76. VLT/FORS2 spectra of GRB 030323
  77. GRB030323, ROTSE-III detection of possible optical counterpart
  78. GRB030323, optical observations
  79. GRB030323, possible optical counterpart
  80. IPN upper limit to a GRB associated with SN2003L
  81. GRB 030227 optical afterglow
  82. GRB 030227: Confirmed Optical Afterglow (S1-A)
  83. GRB 030227: fading of candidate optical afterglow 'S1-A'
  84. GRB030227 - faint tentative OT candidate
  85. GRB 030226: Optical afterglow
  86. GRB030226: Candidate optical afterglow
  87. GRB 030131: marginal optical detection
  88. GRB030131: Candidate Optical Afterglow
  89. GRB 030131, optical observations
  90. GRB030131: Kiso optical limit for corrected position
  91. GRB030131: Optical limits for corrected position
  92. GRB 030131: afterglow candidate
  93. GRB 020819: afterglow candidate
  94. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  95. GRB030115 submm upper limit
  96. GRB 030115: Further IR observations with IRSF/SIRIUS
  97. GRB 030115: Radio detection of IR candidate
  98. GRB 030115: IR observations with IRSF/SIRIUS
  99. GRB030115: R-band counterpart of IR candidate
  100. GRB030115, afterglow candidate

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