Herschel
          
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          -ATLAS: modelling the first strong gravitational lenses

Dye, S.; Negrello, M.; Hopwood, R.; Nightingale, J. W.; Bussmann, R. Shane; Amber, S.; Bourne, N.; Cooray, Asantha; Dariush, A.; Dunne, L.; Eales, Steve; González‐Nuevo, J.; Ibar, E.; Ivison, R. J.; Maddox, S.; Valiante, Elisabetta; Smith, M.

doi:10.1093/mnras/stu305

Cited by 60 publications

(87 citation statements)

References 84 publications

(94 reference statements)

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“…In the intervening period, stars and dark matter become more mixed and thus better aligned with cosmic time. These results are consistent with strong lensing observations (e.g., Sluse et al 2012;Dye et al 2014, Rusu et al 2016. In particular, for galaxies that have stellar axis ratios falling within similar ranges as above, Gavazzi et al (2012) measured an rms scatter of 18…”

Section: Shape Of Luminous and Total Mattersupporting

confidence: 89%

The inner structure of early-type galaxies in the Illustris simulation

Springel

Sluse³

et al. 2017

Monthly Notices of the Royal Astronomical Society

139

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Early-type galaxies provide unique tests for the predictions of the cold dark matter cosmology and the baryonic physics assumptions entering models for galaxy formation. In this work, we use the Illustris simulation to study correlations of three main properties of early-type galaxies, namely, the stellar orbital anisotropies, the central dark matter fractions and the central radial density slopes, as well as their redshift evolution since z = 1.0. We find that lower-mass galaxies or galaxies at higher redshift tend to be bluer in rest-frame colour, have higher central gas fractions, and feature more tangentially anisotropic orbits and steeper central density slopes than their higher-mass or lowerredshift counterparts, respectively. The projected central dark matter fraction within the effective radius shows a very mild mass dependence but positively correlates with galaxy effective radii due to the aperture effect. The central density slopes obtained by combining strong lensing measurements with single aperture kinematics are found to differ from the true density slopes. We identify systematic biases in this measurement to be due to two common modelling assumptions, isotropic stellar orbital distributions and power-law density profiles. We also compare the properties of early-type galaxies in Illustris to those from existing galaxy and strong lensing surveys, we find in general broad agreement but also some tension, which poses a potential challenge to the stellar formation and feedback models adopted by the simulation.

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Section: Shape Of Luminous and Total Mattersupporting

confidence: 89%

The inner structure of early-type galaxies in the Illustris simulation

Springel

Sluse³

et al. 2017

Monthly Notices of the Royal Astronomical Society

139

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“…The retrieved magnification are respectively 7.80 and 17.39 for the HST/WFC3 and ALMA observations. The first value is higher than (but consistent within 2.5σ with) the value tot ∼ 6.3 reported in Dye et al (2014, but the lens was modelled with a Singular Power Law Ellipsoid and resulted to be more spherical than what we find), the second is almost twice the value of µ 880 reported in Bussmann et al (2013), even though it is worth noticing that in that case the lens modeling method was a fully parametric one, with the reconstructed source modeled with a Sersic profile. Anyway, the high value of µ 1.3 is expected since the reconstructed source is compact and peaks close to the lens caustic.…”

Section: Modeling the Emission Of Sdp9supporting

confidence: 88%

“…Optical images of the foreground lens with the Keck telescope at g-and i-bands confirmed that their optical profiles are consistent with elliptical galaxies (Negrello et al 2010).Follow-up observations with the SMA at 880 m (Bussmann et al 2013) and with the Hubble Space Telescope at 1.1 and 1.6 micron confirmed them to be lensed galaxies. Dye et al (2014) modeled the lensed systems as being lensed by elliptical galaxies at redhift 0.6129 ± 0.00005 and 0.7932 ± 0.0012. The magnification factors µ are estimated to be 6.29 and 7.89 (8.8 and 10.9 according to Bussmann et al 2013) respectively for the two galaxies (see these values may be overestimated as they have been evaluated in a poorly sampled spectral region where contamination might enhance the signal in an unpredictable way.…”

Section: Introductionmentioning

confidence: 99%

Chandra and ALMA observations of the nuclear activity in two strongly lensed star-forming galaxies

Massardi

Enia

Negrello

et al. 2018

A&A

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Aims. According to coevolutionary scenarios, nuclear activity and star formation play relevant roles in the early stages of galaxy formation. We aim at identifying them in high redshift galaxies by exploiting high-resolution and sensitivity X-ray and millimetre-wavelength data to confirm the presence or absence of star formation and nuclear activity and their relative role in shaping their SEDs and contributing to their energy budget. Methods. In the current paper we present the data, model and analysis in the X-ray and mm bands for two strongly lensed galaxies, SDP.9 (HATLAS J090740.0-004200) and SDP.11 (HATLAS J091043.1-000322) that we selected in the Herschel-ATLAS catalogues as having an excess emission in the mid-IR regime at redshift > ∼ 1.5, suggesting the presence of a nuclear activity in the early stages of galaxy formation. We observed both of them with Chandra ACIS-S in the X-ray regime and analyzed the high resolution mm data available in the ALMA Science Archive for SDP9, and, by combining the information available in mm, optical and X-ray bands we reconstructed the source morphology.Results. Both the targets were detected in the X-ray, strongly indicating the presence of highly obscured nuclear activity. ALMA observations for SDP9 for continuum and CO(6-5) spectral line with high resolution (0.02arcsec corresponding to ∼ 65 pc at galaxy distance) allowed us to estimate the lensed galaxy redshift to a better accuracy than pre-ALMA estimates (1.5753±0.0003) and to model the emission of the optical, millimetric, and X-ray band emission for this galaxy. We demonstrated that the X-ray emission is generated in the nuclear environment and it strongly support the presence of nuclear activity in this object. On the basis of the X-ray data, we attempted an estimate of the BH properties in these galaxies. Conclusions. By taking advantage of the lensing magnification we identified weak nuclear activity associated with high-z galaxies with large star formation rates, useful to extend the investigation of the relationship between star formation and nuclear activity to two intrinsically less luminous, high-z star forming galaxies than was possible so far. Given our results only for two objects, they solely cannot constrain the evolutionary models, but provide us with interesting hints and set an observational path towards addressing the role of star formation and nuclear activity in forming galaxies.

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“…We also do not show the centroid coordinates due to the uncertainty in the absolute astrometry, although the model uncertainty on the centroid is < 0.03 . Compared to the model of Dye et al (2014), we find a slightly steeper power law index and smaller Einstein radius, but the results are consistent within 2σ. However, we find a more elliptical mass distribution (b/a = 0.68 ± 0.05) compared to that of Dye et al (2014) (b/a = 0.88 ± 0.06).…”

Section: Lens Model Resultssupporting

confidence: 42%

ALMA Observations of the Gravitational Lens SDP.9

Wong

Ishida

Tamura

et al. 2017

ApJL

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We present long-baseline ALMA observations of the strong gravitational lens H-ATLAS J090740.0-004200 (SDP.9), which consists of an elliptical galaxy at z L = 0.6129 lensing a background submillimeter galaxy into two extended arcs. The data include Band 6 continuum observations, as well as CO J=6−5 molecular line observations, from which we measure an updated source redshift of z S = 1.5747. The image morphology in the ALMA data is different from that of the HST data, indicating a spatial offset between the stellar, gas, and dust component of the source galaxy. We model the lens as an elliptical power law density profile with external shear using a combination of archival HST data and conjugate points identified in the ALMA data. Our best model has an Einstein radius of θ E = 0.66 ± 0.01 and a slightly steeper than isothermal mass profile slope. We search for the central image of the lens, which can be used constrain the inner mass distribution of the lens galaxy including the central supermassive black hole, but do not detect it in the integrated CO image at a 3σ rms level of 0.0471 Jy km s −1 .

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Herschel ★ -ATLAS: modelling the first strong gravitational lenses

Cited by 60 publications

References 84 publications

The inner structure of early-type galaxies in the Illustris simulation

The inner structure of early-type galaxies in the Illustris simulation

Chandra and ALMA observations of the nuclear activity in two strongly lensed star-forming galaxies

ALMA Observations of the Gravitational Lens SDP.9

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