No. You will need to use a payment gateway that Atlas is currently set up to integrate with. These include:
To update your payment gateway in Atlas, navigate to Admin > Set Preferences > Application Settings. Click the Credit Card Processing tab, and then click on the blue link that says "Edit/View Credit Card Gateways." You can edit/add your new gateway information into the appropriate fields and click Save.
You may now need to reassign your credit card payment types to use the new gateway that you just added. Go to Admin > Manage Codes > Revenue Codes, and Payment Types. Click on your Credit Card payment type, and make sure that your new Authorize.net gateway is selected in the Credit Card Gateway dropdown menu there.
If you added a new payment type for your new gateway, and you want your online payments to use this payment type, you will also need to go to Admin > Set Preferences > Application Settings. Click on the Online Payments tab. From the "Online Payment's Payment Type" drop down menu, choose your new payment type and Save.