J/MNRAS/394/375 AKARI photometric redshift accuracy (Negrello+, 2009)
Photometric redshift accuracy in AKARI deep surveys.
Negrello M., Serjeant S., Pearson C., Takagi T., Efstathiou A., Goto T.,
Burgarella D., Jeong W.-S., Im M., Lee H.M., Matsuhara H., Oyabu S.,
Wada T., White G.
<Mon. Not. R. Astron. Soc., 394, 375-397 (2009)>
=2009MNRAS.394..375N 2009MNRAS.394..375N
ADC_Keywords: Galaxies, IR ; Redshifts ; Photometry, infrared ;
Photometry, millimetric/submm
Keywords: galaxies: active - galaxies: starburst - infrared: galaxies
Abstract:
We investigate the photometric redshift accuracy achievable with the
AKARI infrared data in deep multiband surveys, such as in the North
Ecliptic Pole field. We demonstrate that the passage of redshifted
polycyclic aromatic hydrocarbons (PAH) and silicate features into the
mid-infrared wavelength window covered by AKARI is a valuable means
to recover the redshifts of starburst galaxies. To this end, we have
collected a sample of ∼60 galaxies drawn from the Great Observatories
Origins Deep Survey-North Field with spectroscopic redshift
0.5≲zspec≲1.5 and photometry from 3.6 to 24um, provided by the
Spitzer, Infrared Space Observatory and AKARI satellites. The
infrared spectra are fitted using synthetic galaxy spectral energy
distributions which account for starburst and active nuclei emission.
For ∼90 per cent of the sources in our sample, the redshift is
recovered with an accuracy |zphot-zspec|/(1+zspec)~<10%. A similar
analysis performed on a set of simulated spectra shows that the AKARI
infrared data alone can provide photometric redshifts accurate to
|zphot-zspec|/(1+zspec)∼10% (1sigma) at z~<2 . At higher redshifts,
the PAH features are shifted outside the wavelength range covered by
AKARI and the photo-z estimates rely on the less prominent 1.6um
stellar bump; the accuracy achievable in this case on (1+z) is
∼10-15%, provided that the active galactic nuclei contribution to
the infrared emission is subdominant. Our technique is no more prone
to redshift aliasing than optical-ultraviolet photo-z, and it may be
possible to reduce this aliasing further with the addition of
submillimetre and/or radio data.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 177 59 *List of IR sources with spectroscopic redshift
drawn from the GOODS-N field,
table3.dat 103 59 Best SED fit parameters obtained for the sample
of IR sources listed in Table 2
--------------------------------------------------------------------------------
Note on table2.dat: by cross-matching the source lists of Aussel et al.
(1999, Cat. J/A+A/342/313) and Teplitz et al. (2005, Cat.
J/ApJ/634/128) with the Spitzer and AKARI catalogues in the same
field. The source positions reported here are those of the
spectroscopic counterpart.
--------------------------------------------------------------------------------
See also:
II/297 : AKARI/IRC mid-IR all-sky Survey (ISAS/JAXA, 2010)
II/298 : AKARI/FIS All-Sky Survey Point Source Cat. (ISAS/JAXA, 2010)
J/A+A/342/313 : ISO HDF observations from PRETI method (Aussel+, 1999)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Sequential number (<[NSP2009] IDNN> in Simbad)
6- 7 I2 h RAh Spectroscopic right ascension (J2000)
9- 10 I2 min RAm Spectroscopic right ascension (J2000)
12- 16 F5.2 s RAs Spectroscopic right ascension (J2000)
18 A1 --- DE- Spectroscopic declination sign (J2000)
19- 20 I2 deg DEd Spectroscopic declination (J2000)
22- 23 I2 arcmin DEm Spectroscopic declination (J2000)
25- 29 F5.2 arcsec DEs Declination (J2000) Spectroscopic position
31- 36 F6.4 --- zs Spectroscopic redshift
38- 42 F5.1 uJy F3.6 Flux at 3.6um
44- 46 F3.1 uJy E_F3.6 Error on F3.6(upper limit)
48- 50 F3.1 uJy e_F3.6 Error on F3.6(lower limit)
52- 56 F5.1 uJy F4.5 Flux at 4.5um
58- 60 F3.1 uJy E_F4.5 Error on F4.5(upper limit)
62- 64 F3.1 uJy e_F4.5 Error on F4.5(lower limit)
66- 70 F5.1 uJy F5.8 Flux at 5.8um
72- 74 F3.1 uJy E_F5.8 Error on F5.8(upper limit)
76- 78 F3.1 uJy e_F5.8 Error on F5.8(lower limit)
80- 84 F5.1 uJy F8.0 Flux at 8.0um
86- 88 F3.1 uJy E_F8.0 Error on F8.0(upper limit)
90- 92 F3.1 uJy e_F8.0 Error on F8.0(lower limit)
94- 99 F6.1 uJy F24 Flux at 24um
101-104 F4.1 uJy E_F24 Error on F24(upper limit)
106-109 F4.1 uJy e_F24 Error on F24(lower limit)
111 A1 --- l_F6.5 Limit flag on F6.5
112-114 I3 uJy F6.5 ?=- Flux at 6.5um
116-117 I2 uJy E_F6.5 ? Error on F6.5(upper limit)
119-120 I2 uJy e_F6.5 ? Error on F6.5(lower limit)
122 A1 --- l_F15 Limit flag on F15
123-125 I3 uJy F15 ?=- Flux at 15um
127-128 I2 uJy E_F15 ? Error on F15(upper limit)
130-131 I2 uJy e_F15 ? Error on F15(lower limit)
133-137 F5.1 uJy F11 Flux at 11um
139-140 I2 uJy E_F11 Error on F11(upper limit)
142-143 I2 uJy e_F11 Error on F11(lower limit)
145-148 I4 uJy F18 Flux at 18um
150-152 I3 uJy E_F18 Error on F18(upper limit)
154-156 I3 uJy e_F18 Error on F18(lower limit)
158-160 I3 uJy F16 ?=- Flux at 16um
162-163 I2 uJy E_F16 ? Error on F16(upper limit)
165-166 I2 uJy e_F16 ? Error on F16(lower limit)
168-177 A10 --- OName HDF name (HDFPMNNN,
<[ACE99] HDF PMN.NN> in Simbad)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Sequential number (<[NSP2009] IDNN> in Simbad)
5 A1 --- n_ID [*] Source with uncertain IR counterpart (1)
7- 12 F6.4 --- zs Spectroscopic redshift
14- 17 F4.2 --- zp Photometric redshift
19- 22 F4.2 --- E_zp Error on zp (upper value)(99% confidence limit)
24- 27 F4.2 --- e_zp Error on zp (lower value)(99% confidence limit)
29- 33 F5.2 --- Rchi2 Minimum reduced χ2 (χ2(min)/ν)
35 I1 --- v Number of degrees of freedom ν
37- 38 A2 --- l_Pchi2 [< ] Limit flag on Pchi2
39- 43 F5.3 --- Pchi2 Probability associated to the minimum χ2
45- 48 F4.2 Gyr Age Age of the starburst
50- 52 F3.1 --- Theta Compactness factor (4)
54- 56 A3 --- Ext [MW SMC LMC] Type of extinction curve
58- 59 I2 deg view ?=- Viewing angle θview
of the AGN dust torus
61- 65 F5.2 [solLum] logLSB Luminosity contributed by the starburst
component (2)
67- 71 F5.2 [solLum] logLAGN ?=- Luminosity contributed by the AGN
component (2)
73- 76 F4.2 --- zp2 Second photometric redshift (3)
78- 81 F4.2 --- E_zp2 Error on zp2 (upper value) (3)
83- 86 F4.2 --- e_zp2 Error on zp2 (lower value) (3)
88- 93 F6.3 --- Rchi22 Second minimum reduced χ2 (3)
95 I1 --- v2 Second number of degrees of freedom (3)
97- 98 A2 --- l_Pchi22 [< ] Limit flag on Pchi22 (3)
99-103 F5.3 --- Pchi22 Probability associated to the second
minimum χ2 (3)
--------------------------------------------------------------------------------
Note (1): * marks the sources with an uncertain counterpart at AKARI and
ISO wavebands.
Note (2): Best-fitting luminosities have been derived integrating the
rest-frame SED from 0.1 to 1000um.
Note (3): results obtained by setting a priori the AGN fraction, f2, to
zero and fitting the observed SED with the starburst SED templates alone.
Note (4): the compactness factor Θ expresses the matter concentration,
with the mean density being higher for smaller values of Θ.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Jul-2010