KIDS1748825 UCMG HST+VIMOS DATA

[KiaraSpin]

On may 8-9 the HST made two orbits around the galaxy KIDS1748825, possibly the first ultra-compact massive strong gravitational lens ever discovered.

After obtaining VIMOS spectra of the galaxy, which showed some emission lines corresponding to a tiny little "blob" (perhaps arc) near by the early-type compact galaxy (figure 1), we applied and obtained HST WFC2 data in two filters: F390W and F814W. We hope that thanks to the very good spatial resolution of HST, in the blue filter, the possible source will clearly appear as arc (if this is a lensing event). The red filter would have help in characterize and model the lens (obtain an effective radius to confirm thew ultra-compactness, in primis) The reduced (directly from them!!!) images are showed in FIGURE 2. I might see some "hints" for an arc in the blue filter image... however it is very faint, if there at all, and in the "wrong" location if compared with VIMOS and KiDS images of Fig.1.

PS The other object in the field of view has also a ETG spectrum at a redshift slightly higher but very closer to the one of the lens (z=0.4006).

[KiaraSpin]

FIGURE 1:

Left: The uppermost panel show a 25" x 25" rgb image from KIDS, the other two panels show the VIMOS field-of-view in two different wavelength, one of which ((6460A) hightlights the O[II] emission of the source. Right: One-dimensional spectra of the lens (up) and the source (down) are plotted in black with a sky spectrum overplotted in blue. The main absorption lines of the lens, as well Oxigen emission lines of the source, are highlighted with red arrows. Grey zones are region of the spectra affected by telluric atmospheric absorptions.

[KiaraSpin]

FIGURE 2: HST imaqes in the F390 (left) and F814(right) filters.

[KiaraSpin]

Questions for @MariaAngelaRaj and @nrnapolita : I noticed that the what you say is g-band, corresponds to FILTER =F814 and viceversa (r-band, which we do not have at all, corresponds to the bluer filter, F390W). I guess the header info is correct, but can you double check?

Here you find the residuals (upper panels) and the original image (lower panel) for F814 (left) and F390W(right)

[KiaraSpin]

GM 21/05 Should we say few words about this system during the VST meeting? We got HST, hoping this was a lens. Unfortunately it is not. However, we have extended kinematics on this galaxy (VIMOS), we can model the HST images and make a Jeans analysis
AI @MariaAngelaRaj improve model and get structural parameters.

[KiaraSpin]

GM 18/06 This issue is very similar to another, which Chiara just closed (#5) Please refer to this one if you have further updates

[KiaraSpin]

GM 18/07 AI Nicola: provide a model with photometry+kinematics for this system. AI Crescenzo: provide references to Nicola on other papers doing the same with IFU

[KiaraSpin]

GM 15/10 This is not a lens, but still we will derive spatially resolved kinematics (VIMOS) and dynamical model (HST) studying for the first time the internal structure of an UCMG. AI Nicola : working on the dynamical model

[KiaraSpin]

GM 22/10 Chiara extracted new aperture spectra (pseudo circular annuli), and then re-run PPXF on the new spectra.

FOUR MOMENTS Central V = 47.7+-16.2, Sigma=227.1+-13.6, h3=0.003+-0.0046, h4= 0.08+-0.039 Aperture1 V= 88.7+- 40.3, Sigma=195.5+-56.3, h3=-0.0089+-0.06, h4=0.004+-0.095
Aperture2 V=152.4+- 51.0, Sigma=177.5+-52.9, h3=0.000298+-0.24, h4=0.0015+-0.124

TWO MOMENTS Central V= 49.13+-11.45, Sigma=226.2+-12.56 Aperture1 V= 81.96+-36.62, Sigma=184.27+-35.62 Aperture2 V= 88.26+-55.44, Sigma=176.09+-55.44 Aperture3 V= 61.83+-45.97, Sigma=141.69+-41.47

This is the best Chiara can do... AI Peppe: try to run the ppxf_gui and get an independent estimation of the kinematics. AI Nicola: work on the dynamical model

[KiaraSpin]

GM 22/10 AI Chiara&Peppe finalize spatially resolved kinematics AI Nicola: finalize dynamical model

[KiaraSpin]

UPDATE 23 NOVEMBER 2018 Dear all, I attach here a report of the work I have been doing on KIDS1748. In particular, I explain the procedures I undertook to extract the 1D spectra in "pseudo-circular-anulii" apertures.

Now the spectra have been sent to Peppe which will run his ppxf+bootstrapping with new functions to improve results in the case of low S/N and noisy spectra.

REPORT_CS.pdf

[KiaraSpin]

GM 17/12/2018 AI @nrnapolita : work on the paper...

[nrnapolita]

Double chack for @KiaraSpin and @gdago Is the file nicola_compatta _wei _metal _age _MEAN _new.cat the latest one to use?

[gdago]

It seems to be the one. I cannot confirm it because my pc in Santiago is currently shut down and I cannot reach it at the moment.

But should be the last one I sent you via Skype.

Il giorno lun 11 feb 2019 alle ore 13:19 Nicola R. Napolitano < notifications@github.com> ha scritto:

Double chack for @KiaraSpin https://github.com/KiaraSpin and @gdago https://github.com/gdago Is the file nicola_compatta _wei _metal _age _MEAN _new.cat the latest one to use?

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/nrnapolita/KIWI_LSST/issues/19#issuecomment-462308345, or mute the thread https://github.com/notifications/unsubscribe-auth/AVKdxCBo-FIddOfeVkLOHsM1_St8mISQks5vMV_EgaJpZM4T9nHv .

-- Giuseppe D'Ago, PhD Postdoctoral researcher

Instituto de AstrofísicaAvenida Vicuña Mackenna 4860, MaculSantiago, Chile

[nrnapolita]

Some quite final MCMC model for the galaxy, isotropic velocity ellipsoid. The MCMC seems to favor lower concentration than standard Chi2, now marginally consistent with expectation from Planck cosmological parameters. The top-light IMF (\delta M/L= M/L/M/L_Chab) seems quite robust and it is even more top-light than found with previous models (\delta M/L= 1.9). I have plotted the expected h_4 paramter to the estimate from the innermost bins and the isotropic model is fully consistent with the observed h_4 values. However some little anisotropy might give a quite bettere fit to the VD. Things to check: 1) the stellar mass is from optical colours, now we have also NIR @ctortora; 2) anisotropy?

[nrnapolita]

@KiaraSpin please provide literature with looser constraints on deltaIMF

[KiaraSpin]

Here some reference of lensing+dynamics+ (sometimes SPS) to constrain total vs stellar mass or fraction of internal dark matter, or IMF mismatch parameter.

Different data (better), different methods, but always larger errors... https://arxiv.org/pdf/1410.1881.pdf https://iopscience.iop.org/article/10.1088/0004-637X/709/2/1195/pdf https://iopscience.iop.org/article/10.1088/0004-637X/724/1/511/pdf http://adsabs.harvard.edu/abs/2011MNRAS.415.2215B http://adsabs.harvard.edu/abs/2013MNRAS.428.3183D https://arxiv.org/pdf/1307.4759.pdf https://arxiv.org/pdf/1111.4215.pdf

[nrnapolita]

@KiaraSpin: I thought you said the larger uncertainties were form similar analysis but now you are mentioning only lensing+dynamics. I guess I commented that you might expect that the combination of techniques, while on one hand might reduce systematics, on the other increases the errors. I am not surprised that they get larger errorbars of the IMF mismatch parameter.

[mariorpd13]

Just a probably silly comment: if you have very small errors, but large systematics, I guess that this means that something is missing in the error budget, which should include the effect of the systematics... ?

On 21/05/19 13:58, Nicola R. Napolitano wrote:

@KiaraSpin https://github.com/KiaraSpin: I thought you said the larger uncertainties were form similar analysis but now you are mentioning /only/ lensing+dynamics. I guess I commented that you might expect that the combination of techniques, while on one hand might reduce systematics, on the other increases the errors. I am not surprised that they get larger errorbars of the IMF mismatch parameter.

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[nrnapolita]

here the only systematics can come from the anisotropy which they generally don’t constraint with the h4 parameter. I checked against the h4 estimates and the prediction are reasonably ok in the center. If h4 is good enough there, then the isotropic assumption is fine and there are no large systematics.

Nicola

On 21 May 2019, at 20:16, mariorpd13 notifications@github.com wrote:

Just a probably silly comment: if you have very small errors, but large systematics, I guess that this means that something is missing in the error budget, which should include the effect of the systematics... ?

On 21/05/19 13:58, Nicola R. Napolitano wrote:

@KiaraSpin https://github.com/KiaraSpin: I thought you said the larger uncertainties were form similar analysis but now you are mentioning /only/ lensing+dynamics. I guess I commented that you might expect that the combination of techniques, while on one hand might reduce systematics, on the other increases the errors. I am not surprised that they get larger errorbars of the IMF mismatch parameter.

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/nrnapolita/KIWI_LSST/issues/19?email_source=notifications&email_token=ADSHL3OWO2JL43EYPUIWWTDPWPPYFA5CNFSM4E7WOHX2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODV3VQII#issuecomment-494360609, or mute the thread https://github.com/notifications/unsubscribe-auth/ADSHL3PM6UO3BPBNSPXVFZTPWPPYFANCNFSM4E7WOHXQ.

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Prof. Nicola R. Napolitano School of Physics and Astronomy Sun Yat-sen University, Guangzhou, Zhuhai Campus 2 Daxue Road, Tangjia, Zhuhai, Guangdong 519082, P.R. China
Office 215, Building #18, Skype: nnapolita WeChat: nrnapolita

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