J-PLUS: Synthetic galaxy catalogues with emission lines for photometric surveys

We present a synthetic galaxy lightcone specially designed for narrow-band optical photometric surveys. To reduce time-discreteness effects, unlike previous works, we directly include the lightcone construction in the L-Galaxies semi-analytic model applied to the subhalo merger trees of the Millennium simulation. Additionally, we add a model for the nebular emission in star-forming regions, which is crucial for correctly predicting the narrow- and medium-band photometry of galaxies. Specifically, we consider, individually for each galaxy, the contribution of 9 different lines: Lyα (1216 Å), Hβ (4861 Å), Hα (6563 Å), [O II] (3727 Å, 3729 Å), [O III] (4959 Å, 5007 Å), [Ne III] (3870 Å), [O I] (6300 Å), [N II] (6548 Å, 6583 Å), and [S II] (6717 Å, 6731 Å). We validate our lightcone by comparing galaxy number counts, angular clustering, and Hα, Hβ, [O II], and [O III]5007 luminosity functions to a compilation of observations. As an application of our mock lightcones, we generated catalogues tailored for J-PLUS, a large optical galaxy survey featuring five broad-band and seven medium-band filters. We study the ability of the survey to correctly identify, with a simple three-filter method, a population of emission-line galaxies at various redshifts. We show that the 4000 Å break in the spectral energy distribution of galaxies can be misidentified as line emission. However, all significant excess (> 0.4 mag) can be correctly and unambiguously attributed to emission-line galaxies. Our catalogues are publicly released to facilitate their use in interpreting narrow-band surveys and in quantifying the impact of line emission in broad-band photometry.

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Properties of LBGs with [OIII] detection at z ∼ 3.5

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935975 ◽

2019 ◽

Vol 631 ◽

pp. A123 ◽

Cited By ~ 1

Author(s):

Fang-Ting Yuan ◽

Denis Burgarella ◽

David Corre ◽

Veronique Buat ◽

Médéric Boquien ◽

...

Keyword(s):

Physical Properties ◽

Emission Line ◽

Near Infrared ◽

Spectral Energy Distribution ◽

Formation Rate ◽

Line Emission ◽

Stellar Mass ◽

Spectral Energy ◽

Emission Data ◽

The Impact

Context. Nebular emission lines are critical to measure physical properties in the ionized gas (e.g., metallicity, the star formation rate, or dust attenuation). They also account for a significant fraction of broadband fluxes, in particular at the highest redshifts, and therefore can strongly affect the determination of other physical properties, such as the stellar mass, which are crucial in shaping our understanding of galaxy formation and evolution. Aims. We investigate a sample of 51 Lyman break galaxies at 3.0 < zspec < 3.8 with detected [OIII] line emissions and estimated the physical properties of these galaxies to examine the impact of including nebular emission data in the Spectral energy distribution (SED) fitting. Methods. We used the Code Investigating GALaxy Emission (CIGALE) to fit the rest-frame ultraviolet-to-near-infrared SEDs of these galaxies and their emission line data simultaneously. We ran CIGALE with and without the nebular model or the emission line data, and compare the results to show the importance of including the nebular emission line data in the SED fitting. Results. We find that without the nebular model, the SED fitting overestimates the stellar mass due to the strong [OIII] lines that are redshifted to the Ks-band, which is consistent with previous results. The emission line data are necessary to constrain the nebular model in the SED fitting. We examine the Ks-band excess, which is mostly used to estimate the emissions of the [OIII]+Hβ lines when there is no spectral data, and we find that the estimation and observation are statistically consistent. However, the difference can reach up to more than 1 dex in some catastrophic cases, which shows the importance of obtaining spectroscopic measurements for these lines. We also estimate the equivalent width of the Hβ absorption and find it negligible compared to the Hβ emission. Conclusions. Line emission is important to constrain the nebular models and to obtain reliable estimates of the physical properties of galaxies. These data should be taken into account in the SED fitting.

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The Nature of the Emission-line Nebulae in Powerful Far-infrared Galaxies

International Astronomical Union Colloquium ◽

10.1017/s025292110000542x ◽

1990 ◽

Vol 124 ◽

pp. 409-413

Author(s):

Lee Armus ◽

Timothy M. Heckman ◽

George K. Miley

Keyword(s):

Emission Line ◽

Narrow Band ◽

Broad Band ◽

Far Infrared ◽

Interacting Galaxies ◽

Spectral Energy ◽

Infrared Galaxies ◽

Energy Distributions ◽

Infrared Spectral ◽

The Mean

AbstractWe discuss our program of narrow-band (Hα + [Nil]) imaging of a sample of 30 powerful far-infrared galaxies (FIRG’s) chosen to have far-infrared spectral energy distributions similar to the prototype FIRG’s Arp 220, NGC 3690, NGC 6240, and M82. The emission-line nebulae of these IR color-selected sample (ICSS) galaxies as a class are both impressively large (mean half light radius, r ~1.3 Kpc, and mean diameter, D ~16 Kpc) and luminous (LTOT ~108 Lo; uncorrected for internal extinction). The mean total Hα + [Nil] luminosity of the FIRG’s is comparable to that found for pairs of optically selected interacting galaxies (Bushouse, Lamb, and Werner 1988), but is a factor of ~5 greater than that of isolated spirals (Kennicutt and Kent 1983). Only ~25% of the nearby (z ≤ 0.10) FIRG’s have morphologies suggesting that large HII~regions contribuí significantly to their emission-line appearance. The broad-band morphologies of our IR color-selected galaxies fall into three major categories. Nearly 75% are single galaxy systems, with the remaining FIRG’s being either multiple nuclei systems, or members of interacting pairs. Since we see few (10%) currently interacting FIRG’s, yet many (80%) with highly distorted continuum morphologies, our IR color criteria may be preferentially selecting galaxies that have undergone highly inelastic, rapidly merging interactions.

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The AGN contribution to the UV–FIR luminosities of interacting galaxies and its role in identifying the main sequence

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2813 ◽

2020 ◽

Vol 499 (3) ◽

pp. 4325-4369

Author(s):

Andrés F Ramos Padilla ◽

M L N Ashby ◽

Howard A Smith ◽

Juan R Martínez-Galarza ◽

Aliza G Beverage ◽

...

Keyword(s):

Star Formation ◽

Main Sequence ◽

Spectral Energy Distribution ◽

Broad Band ◽

Far Infrared ◽

Stellar Mass ◽

Spectral Energy ◽

Star Forming ◽

Nuclear Regions ◽

The Impact

ABSTRACT Emission from active galactic nuclei (AGNs) is known to play an important role in the evolution of many galaxies including luminous and ultraluminous systems (U/LIRGs), as well as merging systems. However, the extent, duration, and exact effects of its influence are still imperfectly understood. To assess the impact of AGNs on interacting systems, we present a spectral energy distribution (SED) analysis of a sample of 189 nearby galaxies. We gather and systematically re-reduce archival broad-band imaging mosaics from the ultraviolet to the far-infrared using data from GALEX, SDSS, 2MASS, IRAS, WISE, Spitzer, and Herschel. We use spectroscopy from Spitzer/IRS to obtain fluxes from fine-structure lines that trace star formation and AGN activity. Utilizing the SED modelling and fitting tool cigale, we derive the physical conditions of the interstellar medium, both in star-forming regions and in nuclear regions dominated by the AGN in these galaxies. We investigate how the star formation rates (SFRs) and the fractional AGN contributions (fAGN) depend on stellar mass, galaxy type, and merger stage. We find that luminous galaxies more massive than about $10^{10} \,\rm {M}_{*}$ are likely to deviate significantly from the conventional galaxy main-sequence relation. Interestingly, infrared AGN luminosity and stellar mass in this set of objects are much tighter than SFR and stellar mass. We find that buried AGNs may occupy a locus between bright starbursts and pure AGNs in the fAGN–[Ne v]/[Ne ii] plane. We identify a modest correlation between fAGN and mergers in their later stages.

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MCSED: A Flexible Spectral Energy Distribution Fitting Code and Its Application to z ∼ 2 Emission-line Galaxies

The Astrophysical Journal ◽

10.3847/1538-4357/ab9f3c ◽

2020 ◽

Vol 899 (1) ◽

pp. 7

Author(s):

William P. Bowman ◽

Gregory R. Zeimann ◽

Gautam Nagaraj ◽

Robin Ciardullo ◽

Caryl Gronwall ◽

...

Keyword(s):

Energy Distribution ◽

Emission Line ◽

Spectral Energy Distribution ◽

Spectral Energy ◽

Distribution Fitting ◽

Emission Line Galaxies

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The challenging SED of AP Librae

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312009532 ◽

2011 ◽

Vol 7 (S284) ◽

pp. 411-413 ◽

Cited By ~ 3

Author(s):

David Sanchez ◽

Berrie Giebels ◽

Pascal Fortin ◽

Keyword(s):

Spectral Energy Distribution ◽

Broad Band ◽

Low Frequency ◽

Theoretical Models ◽

Intermediate Frequency ◽

High Energy ◽

Spectral Energy ◽

Broad Band Emission ◽

Band Emission ◽

Bl Lac

AbstractMatching the broad-band emission of active galaxies with the predictions of theoretical models can be used to derive constraints on the properties of the emitting region and to probe the physical processes involved. AP Librae is the third low frequency peaked BL Lac (LBL) detected at very high energy (VHE, E>100GeV) by an Atmospheric Cherenkov Telescope; most VHE BL Lacs (34 out of 39) belong to the high-frequency and intermediate-frequency BL Lac classes (HBL and IBL). LBL objects tend to have a higher luminosity with lower peak frequencies than HBLs or IBLs. The characterization of their time-averaged spectral energy distribution is challenging for emission models such as synchrotron self-Compton (SSC) models.

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The Hα line emission of the Be star β Psc: the last 40 yr

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2789 ◽

2020 ◽

Vol 501 (1) ◽

pp. 747-755

Author(s):

Ronaldo S Levenhagen ◽

Marcos P Diaz ◽

Eduardo B Amôres ◽

Nelson V Leister

Keyword(s):

Additional Data ◽

State Of The Art ◽

Spectral Energy Distribution ◽

Line Emission ◽

Spectral Energy ◽

Line Profiles ◽

Gas Density ◽

Geometric Deformation ◽

Be Star ◽

Effects Of Rotation

ABSTRACT A study on the photosphere and disc of the Be star β Psc is presented. We recover almost 40 yr of high-resolution spectroscopic observations and additional data gathered from the BeSS data base. We evaluate the photospheric parameters from the spectral energy distribution (SED) and fittings of state-of-the-art non-LTE model atmospheres to observed helium, carbon, silicon, and magnesium line profiles. Our models include the stellar geometric deformation as well as the co-latitude dependence of temperature and gravity, aiming to derive the effects of rotation on the stellar parameters. We estimate the circumstellar disc parameters from the fitting of models assuming different disc properties, namely its radius and gas density profile. The disc inclination angle i is constrained from the fittings of He i 4471 Å, Mg ii 4481 Å, C ii 4267 Å, and Si ii 4128, 4132 Å lines with gravity darkened models. Our findings, based on model fittings, suggest that during the last 40 yr, the disc radius changed within the interval 5.5 ≤ Rd ≤ 7.8 $R/R_{*}\,$, the disc base gas density within 5 × 10−13 ≤ ρ ≤ 1 × 10−12 g cm−3, while the radial power-law density index m assumed values between 2.0 and 2.3. These results are in agreement with recent works dealing with spectroscopic and interferometric measurements of this object.

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Constraining X-ray emission in HBL blazars using multiwavelength observations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1537 ◽

2020 ◽

Vol 496 (2) ◽

pp. 1295-1306

Author(s):

Alicja Wierzcholska ◽

Stefan J Wagner

Keyword(s):

Spectral Energy Distribution ◽

Broad Band ◽

Neutral Hydrogen ◽

High Energy ◽

Host Galaxy ◽

Spectral Energy ◽

Additional Absorption ◽

X Ray ◽

Uv Excess ◽

Survey Results

ABSTRACT The X-ray spectrum of extreme high-energy peaked BL Lac-type blazars is located in the synchrotron branch of the broad-band spectral energy distribution (SED), at energies below the peak. A joint fit of the extrapolated X-ray spectra together with a host galaxy template allows characterizing the synchrotron branch in the SED. The X-ray spectrum is usually characterized either with a pure or a curved power-law model. In the latter case, however, it is hard to distinguish an intrinsic curvature from excess absorption. In this paper, we focus on five well-observed blazars: 1ES 0229+200, PKS 0548−322, RX J 1136+6737, 1ES 1741+196, and 1ES 2344+514. We constrain the infrared to X-ray emission of these five blazars using a model that is characterized by the host galaxy, spectral curvature, absorption, and ultraviolet (UV) excess to separate these spectral features. In the case of four sources, namely 1ES 0229+200, PKS 0548−322, 1ES 1741+196, and 1ES 2344+514, the spectral fit with the atomic neutral hydrogen from the Leiden Argentina Bonn Survey results in a significant UV excess present in the broad-band SED. Such excess can be interpreted as an additional component, for example, a blue bump. However, in order to describe spectra of these blazars without such excess, additional absorption to the atomic neutral hydrogen from the Leiden Argentina Bonn Survey is needed.

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Temporal correlation between the optical and γ-ray flux variations in the blazar 3C 454.3

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz941 ◽

2019 ◽

Vol 486 (2) ◽

pp. 1781-1795 ◽

Cited By ~ 8

Author(s):

Bhoomika Rajput ◽

C S Stalin ◽

S Sahayanathan ◽

Suvendu Rakshit ◽

Amit Kumar Mandal

Keyword(s):

Spectral Energy Distribution ◽

Broad Band ◽

Temporal Correlation ◽

Lorentz Factor ◽

Degree Of Polarization ◽

Spectral Energy ◽

Long Duration ◽

Γ Ray ◽

Optical Flux ◽

Optical Flare

ABSTRACT Blazars show optical and γ-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical, ultraviolet, X-ray, and γ-ray energies, spanning about 9 yr from 2008 August to 2017 February. We have identified four time intervals (epochs), A, B, D, and E, when the source showed large-amplitude optical flares. In epochs A and B the optical and γ-ray flares are correlated, while in D and E corresponding flares in γ-rays are weak or absent. In epoch B the degree of optical polarization strongly correlates with changes in optical flux during a short-duration optical flare superimposed on one of long duration. In epoch E the optical flux and degree of polarization are anticorrelated during both the rising and declining phases of the optical flare. We carried out broad-band spectral energy distribution (SED) modelling of the source for the flaring epochs A,B, D, and E, and a quiescent epoch, C. Our SED modelling indicates that optical flares with absent or weak corresponding γ-ray flares in epochs D and E could arise from changes in a combination of parameters, such as the bulk Lorentz factor, magnetic field, and electron energy density, or be due to changes in the location of the γ-ray-emitting regions.

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Broad-band spectral energy distribution of the X-ray transient Swift J1745−26 from outburst to quiescence

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935720 ◽

2020 ◽

Vol 637 ◽

pp. A2

Author(s):

Sylvain Chaty ◽

Francis Fortin ◽

Alicia López-Oramas

Keyword(s):

Energy Distribution ◽

Light Curve ◽

Spectral Energy Distribution ◽

Broad Band ◽

Spectral Energy ◽

X Ray ◽

Upper Limit ◽

Spectral Break ◽

Hard State ◽

Low Mass

Aims. We aim to analyse our study of the X-ray transient Swift J1745−26, using observations obtained from its outburst in September 2012, up to its decay towards quiescence in March 2013. Methods. We obtained optical and infrared observations, through override programme at ESO/VLT with FORS2 and ISAAC instruments, and added archival optical (VLT/VIRCAM), radio and X-ray (Swift) observations, to build the light curve and the broad-band spectral energy distribution (SED) of Swift J1745−26. Results. We show that, during its outburst and also during its decay towards quiescence, Swift J1745−26 SED can be adjusted, from infrared up to X-rays, by the sum of both a viscous irradiated multi-colour black body emitted by an accretion disc, and a synchrotron power law at high energy. In the radio domain, the SED arises from synchrotron emission from the jet. While our SED fitting confirms that the source remained in the low/hard state during its outburst, we determine an X-ray spectral break at frequency 3.1 ≤ νbreak ≤ 3.4 × 1014 Hz, and a radio spectral break at 1012 Hz ≤ νbreak ≤ 1013 Hz. We also show that the system is compatible with an absorption AV of ∼7.69 mag, lies within a distance interval of D ∼ [2.6 − 4.8] kpc with an upper limit of orbital period Porb = 11.3 h, and that the companion star is a late spectral type in the range K0–M0 V, confirming that the system is a low-mass X-ray binary. We finally plot the position of Swift J1745−26 on an optical-infrared – X-ray luminosity diagram: its localisation on this diagram is consistent with the source staying in the low-hard state during outburst and decay phases. Conclusions. By using new observations obtained at ESO/VLT with FORS2 and ISAAC, and adding archival optical (VLT/VIRCAM), radio and X-ray (Swift) observations, we built the light curve and the broad-band SED of Swift J1745−26, and we plotted its position on an optical-infrared – X-ray luminosity diagram. By fitting the SED, we characterized the emission of the source from infrared, via optical, up to X-ray domain, we determined the position of both the radio and X-ray spectral breaks, we confirmed that it remained in the low-hard state during outburst and decay phases, and we derived its absorption, distance interval, orbital period upper limit, and the late-type nature of companion star, confirming Swift J1745−26 is a low-mass X-ray binary.

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The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS J1222+0413

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1193 ◽

2019 ◽

Vol 487 (1) ◽

pp. 181-197 ◽

Cited By ~ 4

Author(s):

Daniel Kynoch ◽

Hermine Landt ◽

Martin J Ward ◽

Chris Done ◽

Catherine Boisson ◽

...

Keyword(s):

Near Infrared ◽

Uv Spectroscopy ◽

Spectral Energy Distribution ◽

Broad Band ◽

Physical Models ◽

Spectral Energy ◽

Narrow Line ◽

Relativistic Jet ◽

Γ Ray ◽

Apply Physical

ABSTRACT We present a multifrequency study of PKS J1222+0413 (4C +04.42), currently the highest redshift γ-ray emitting narrow-line Seyfert 1 (γ-NLS1). We assemble a broad spectral energy distribution (SED) including previously unpublished datasets: X-ray data obtained with the NuSTAR and Neil Gehrels Swift observatories; near-infrared, optical, and UV spectroscopy obtained with VLT X-shooter; and multiband radio data from the Effelsberg telescope. These new observations are supplemented by archival data from the literature. We apply physical models to the broad-band SED, parametrizing the accretion flow and jet emission to investigate the disc–jet connection. PKS J1222+0413 has a much greater black hole mass than most other NLS1s, MBH ≈ 2 × 108 M$\odot$, similar to those found in flat spectrum radio quasars (FSRQs). Therefore this source provides insight into how the jets of γ-NLS1s relate to those of FSRQs.

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