VII/298 QUAC. QUasar Atlas and Catalogue (QUAC coll., 2002-2014)
QUAC: QUasar Atlas and Catalogue.
QUAC collaboration
https://www.vialattea.net, 2002-2014
=2025yCat.7298....0Q 2025yCat.7298....0Q
ADC_Keywords: QSOs ; Active gal. nuclei ; BL Lac objects ;
Gravitational lensing ; Redshifts ; Photometry ; Optical
Description:
Due to the fact that they are the farthest sources from the known
Universe, the Quasars (QSO) and the BL Lacertae objects (BL) are not
only the most important aspects either of the cosmological studies and
of the other studies dedicated to far removed from our own objects,
but their studies have started to excite the curiosity and the
interest of a large part of the amatorial Astronomy. This renewed
interest is due to the most advanced technology placed at the modern
amateur astronomer's disposal; this technology is really different
from the technology available 20 years ago.
Nowadays these instruments, equipped with sophisticated CCD cameras,
can easily reached the magnitudes of the historical Palomar
Observatory Sky Survey (POSS), a real myth for entire generations of
people keen on astronomical studies.
We should add that the QSO and BL are optically variables and this
phenomenon has excited many amateur astronomers' curiosity and has
guaranteed them large satisfactions.
It's important to remark that there is the realistic probability
that such an object could have leaved its print image centred
somewhere on a galaxy or on a cluster.
All this makes at least interesting the simple knowledge of the exact
positions of these exotic, celestial objects.
But where are exactly the QSO and the BL and what can we do to
identify them? Their pointed aspect makes them very similar to stars
and so it's very difficult to distinguish these objects from stars.
That's why it's necessary a precise identification.
Sometimes astronomers working in this field publish the maps of the
studied objects only, often using very narrow fields and without
worrying about the quality of reproduction.
In the since now published literature there is not a work which
presents more than 100-200 finding charts of these objects
(usually they present 10-20 units, sometimes some units less) with
well shaped images, while the available catalogue and lists often
contain information and details which are not really interesting for
amateur astronomers.
We have thought to make up for this lack publishing a new work called
QUAC (from QUasar Atlas and Catalogue) which contains homogeneous
information, positions and finding charts.
Information and positions are obtained and calculated consulting
various publications while finding charts are directly obtained from
the digitized POSS plates or SDSS plates.
The most brilliant objects are suitable to be visually observed and
sometimes they are observable with photoelectric-photometers.
The "QUAC" will be subjected to revisions either interesting the
Catalogue section, with the presentation of new objects and other
information, and the Atlas section where we project to propose a
growing number of finding charts.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 1639 3630588 QUasar Atlas and Catalogue (QUAC)
class.dat 150 48 Type definitions
acro.dat 294 772 Acromym definitions
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See also:
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron-Cetty+ 2010)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 17 A17 -- Type Type of the object (1)
19- 60 A42 --- Name First name
62- 63 I2 h RAh Right ascension (J2000)
65- 66 I2 min RAm Right ascension (J2000)
68- 76 F9.6 s RAs [0/60] Right ascension (J2000)
78 A1 --- DE- Declination sign (J2000)
79- 80 I2 deg DEd Declination (J2000)
82- 83 I2 arcmin DEm Declination (J2000)
85- 91 F7.3 arcsec DEs [0/60] Declination (J2000)
93 A1 --- l_z Limit flag on z
94- 102 E9.5 --- z ? Redshift
104 A1 ---- n_z [a] Note on redshift (2)
106 A1 --- Band Band if not V
107 A1 --- l_Vmag Limit falg on Vmag
108- 116 F9.6 mag Vmag ? Magnitude, usually in V, or in Band (3)
119 A1 --- l_B-V Limit flag on B-V
120- 125 F6.3 mag B-V ? B-V colour index
127 A1 --- l_U-B Limit flag on U-B
128- 132 F5.2 mag U-B ? U-B colour index
134- 989 A856 --- Names Names mainly known to identify the
objects (4)
991-1639 A649 --- Ref References to other known publications where
it is possible to get an identification
map (5)
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Note (1): See definitions in class.dat file.
Note (2): Note as follows:
a = (0.5-1.5)
Note (3): magnitude, usually in the V range unless otherwise indicated.
The "O" magnitude is that measured on the "O" plates of the Palomar
Observatory Sky Survey (POSS) or obtained from the USNO-A2 or APM Catalogues
and is related to the B of the Johnson and Morgan system by the following
relationship: B-O = -(0.27±0.06)(B-V) and must therefore be considered with
care both due to its low intrinsic precision and the variability inherent in
many quasars. The "r", "i" and "z" magnitudes are provisionally deduced from
the corresponding bands in the SDSS survey, while those represented with AB
refer to measurements made at 1450 (1+z) m. For the "cQ" and "bQc" objects
the magnitudes are sometimes expressed in the "i" band - the symbol of which
is not always indicated.
Note (4): Names by which the object is best known from the various catalogs.
Where catalog abbreviations are followed by coordinates, these are reported
only once to avoid cluttering the column, also considering that the
coordinates themselves are often provided with different precisions and
styles depending on the publications in which they appear.
For the meanings of the various acronyms and abbreviations, see acro.dat file.
In the case of "cQ" and "bQc," only the relevant catalog number or reference
to the respective survey has been included. In this regard, please note that
the "cQ" and "bQc" have been included anyway, even if their coordinates,
in many cases, correspond to those of objects already included previously.
In these cases, a progressive consolidation is underway.
The same applies to objects included in the LQAC, LQRF, and APK catalogs.
Since the existing catalogs were compiled at very different times and with
technologies of varying precision in multiple spectral regions, we opted
- in identifying the various acronyms - for an error radius of 10" which
represents a good compromise for both the old catalogs and the first space
surveys (IR, UV, X-ray, Gamma); this means that, especially for the latter,
correspondences should be treated with caution.
Note (5): The acronym QUAC means that the finding chart of the object is
available in the Atlas section.
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Byte-by-byte Description of file: class.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Type Type of the object
16-150 A135 --- Def Type definition (1)
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Note (1): R is the ratio of the total Hbeta to the |OIII| 5007 fluxes
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Byte-by-byte Description of file: acro.dat
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Bytes Format Units Label Explanations
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1- 27 A27 --- Accro Acronym
29-109 A81 --- Full Full denomination
111-119 A9 --- Band Band (1)
121-155 A35 --- Type Object type
157-294 A138 --- Refs References
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Note (1): Band as:
Rd = radio
IR (or I) = infrared
R = red
V = visual
B = blue
UV (or U) = ultraviolet
X = X-ray
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History:
Copied at
https://www.vialattea.net/content/osservatorio-sharru/quac/quac-download
(End) Patricia Vannier [CDS] 08-Oct-2025